Apparatus for positioning electronic component holder head and apparatus for transferring electronic component

ABSTRACT

An apparatus for positioning each of a plurality of electronic component holder heads each for holding an electronic component, at a selected one of a plurality of positions of at least one stop station, including a plurality of rotary members each of which is rotatable about a common axis line and is stoppable at the at least one stop station, the electronic component holder heads being carried by the rotary members, respectively, such that each of the holder heads is movable relative to a corresponding one of the rotary members in a direction parallel to the common axis line, and (a) a circumferential position selecting device which selects, for the stop station, one of a plurality of circumferential positions which are spaced from each other in a direction of rotation of the rotary members about the common axis line, so that at least one of the rotary members is stopped at the selected circumferential position and accordingly the electronic component holder head carried by the one rotary member is positioned at the selected one position, and/or (b) an axial position selecting device which selects, for the stop station, one of a plurality of axial positions which are spaced from each other in the direction parallel to the common axis line, so that at least one of the head holders is positioned at the selected axial position as the selected one position.

This application is a Divisional application of Ser. No. 08/907,882filed on Aug. 11, 1997 and since patented as U.S. Pat. No. 6,168,009which in turn is a Continuation-in-Part of application Ser. No.08/769,700 filed Dec. 18, 1996 and since patented as U.S. Pat. No.5,926,950.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for positioning anelectronic component holder head and an apparatus for transferring anelectronic component (“EC”).

2. Related Art Statement

Japanese Patent Application laid open for inspection under PublicationNo. 2-69999 discloses an EC holder head which is employed by an ECmounting system for mounting one or more ECs on an object such as aprinted circuit board (“PCB”). The prior EC mounting system includes arotatable table which is intermittently rotatable about a vertical axisline, and a plurality of head supporting devices which are supported bythe rotatable table such that the head supporting devices areequiangularly spaced from each other about the vertical axis line of-the rotatable table and such that each of the head supporting devices ismovable in a direction parallel to the vertical axis line. Each of thehead supporting devices supports an EC holder head such that the ECholder head extends parallel to the vertical axis line of the rotatabletable and such that the EC holder head is rotatable about an axis linethereof. As the rotatable table is intermittently rotated, each of thehead supporting devices is sequentially stopped at each of the samenumber of stop stations as that of the supporting devices. At an ECsucking station as one of the stop stations, each of the head supportingdevices is moved up and down by an elevating and lowering device, sothat the EC holder head supported by said each head supporting devicesucks up an EC from an EC supplying device. Meanwhile, at an imagetaking station as one of the stop stations, an image of the EC held bythe EC holder head is taken by an image taking device, so that anangular position error of the EC about an axis line of the EC holderhead is calculated based on the image data provided by the image takingdevice and the calculated angular position error of the EC is correctedby rotating the EC holder head about the axis line thereof. After theangular position error of the EC is corrected, the head supportingdevice is moved to an EC mounting station as one of the stop stations,where the head supporting device is lowered by another elevating andlowering device, so that the EC holder head supported thereby mounts theEC on a PCB.

However, the above-identified prior EC mounting system can stop each ofthe head supporting devices at only one circumferential stop position ineach of the plurality of stop stations, and cannot change or move theonly one circumferential stop position in the circumferential directionof the rotatable table. Likewise, the prior EC mounting system canposition each of the EC holder heads at only one position relative tothe corresponding head supporting device in the direction parallel tothe vertical axis line of the rotatable table, and cannot change or movethe only one relative position in the direction parallel to the verticalaxis line. In addition, the prior EC mounting system can move each ofthe EC holder heads along only one movement path and cannot change ormove at least a portion of the movement path to another path whoseposition in a direction normal to that portion of the movement path isdifferent from that of the portion of the movement path.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide anapparatus wherein at least one of (a) a circumferential orrotating-direction stop position of a rotary member which carries an ECholder head and is rotatable about an axis line while describing acircular locus and (b) a position of the EC holder head relative to therotary member in a direction parallel to the axis line is selectivelychangeable.

It is another object of the present invention to provide an apparatuswhich includes a plurality of rotary members which are rotatable about acommon axis line independently of each other and each of which carriesan EC holder head and wherein at least one of (a) a rotating-directionposition of at least one of the rotary members and (b) a position of theEC holder head carried by at least one of the rotary members relative tosaid one rotary member in a direction parallel to the common axis lineis selectively changeable.

It is another object of the present invention to provide an apparatuswhich includes a drive cam and at least one cam follower which cooperatewith each other to rotate a rotary member and wherein arotating-direction stop position of the rotary member is easily andselectively changeable.

It is another object of the present invention to provide an apparatuswherein a stationary cam and at least one cam follower are employed foreasily and selectively changing a position of an EC holder head relativeto an rotary member in a direction parallel to an axis line about whichthe rotary member is rotatable.

It is another object of the present invention to provide an apparatuswhich includes an EC holder head which is movable along a circularmovement path or an EC holder head which is movable along a straightmovement path and wherein at least one of (a) an on-path stop positionon the circular or straight movement path and (b) anintersecting-direction stop position spaced from the circular orstraight movement path in a direction intersecting the movement path isselectively changeable.

It is another object of the present invention to provide an ECtransferring apparatus which can select, as at least a portion of amovement path along which an EC holder head is movable, one of aplurality of selectable paths which have different positions,respectively, in a direction intersecting that portion of the movementpath.

The present invention provides an EC holder head positioning apparatus,an EC transferring apparatus, and an EC mounting system which have oneor more of the technical features which are described below inrespective paragraphs given parenthesized sequential numbers (1) to(25). Any technical feature which includes another technical featureshall do so by referring, at the beginning, to the number given to thattechnical feature. Thus, two or more of the following technical featuresmay be combined, if appropriate. Each technical feature may beaccompanied by a supplemental explanation, as needed.

(1) According to a first feature of the present invention, there isprovided an apparatus for positioning each of a plurality of electroniccomponent holder heads each for holding an electronic component, at aselected one of a plurality of positions of at least one stop station,comprising a plurality of rotary members each of which is rotatableabout a common axis line and is stoppable at the at least one stopstation, the electronic component holder heads being carried by therotary members, respectively, such that each of the holder heads ismovable relative to a corresponding one of the rotary members in adirection parallel to the common axis line; and at least one of (a) acircumferential position selecting device which selects, for the stopstation, one of a plurality of circumferential positions which arespaced from each other in a direction of rotation of the rotary membersabout the common axis line, so that at least one of the rotary membersis stopped at the selected circumferential position and accordingly theelectronic component holder head carried by the one rotary member ispositioned at the selected one position, and (b) an axial positionselecting device which selects, for the stop station, one of a pluralityof axial positions which are spaced from each other in the directionparallel to the common axis line, so that at least one of the holderheads is positioned at the selected axial position as the selected oneposition. The present positioning apparatus can select one of theplurality of circumferential positions and/or one of the plurality ofaxial positions. Accordingly, in the case where the present positioningapparatus is employed by, e.g., an EC mounting system having an ECsucking station and an EC mounting station, the present apparatus canselect, as an EC sucking position at the EC sucking station or as an ECmounting position at the EC mounting station, one of the plurality ofcircumferential positions so that at least one of the rotary members,i.e., the EC holder head carried on said one rotary member is stopped atthe selected one circumferential position as the EC sucking position oras the EC mounting position. In addition, depending upon a dimension ofan EC as measured in the direction parallel to the common axis line, thepresent apparatus can select, as a stroke of movement of the EC holderhead for sucking the EC or mounting the EC, one of the plurality ofaxial positions spaced from each other in the direction parallel to thecommon axis line, so that the EC holder head is moved to, and positionedat, the selected one axial position corresponding to the stroke ofmovement of the EC holder head. Thus, the present apparatus contributesto improving the EC mounting efficiency of the EC mounting system.

(2) According to a second feature of the present invention whichincludes the first feature (1), the positioning apparatus furthercomprises a rotary member supporting device which supports the rotarymembers such that the rotary members are rotatable about the common axisline independently of each other; and a rotary member rotating devicewhich rotates the rotary members supported by the rotary membersupporting device, independently of each other. Since the rotary membersare rotatable independently of each other, the present positioningapparatus can rotate one of the rotary members while having anotherrotary member stopped at a stop station. Therefore, as will be describedon a preferred embodiment of the present invention, the presentapparatus can shorten a transferring pitch at which each of the rotarymembers is transferred from one stop station to the next stop station.Since this technical feature is combined with the above-indicatedfeature that the present apparatus can select one of the plurality ofcircumferential positions and/or one of the plurality of axialpositions, the present apparatus can enjoy a high EC transferringefficiency of the EC holder heads.

(3) According to a third feature of the present invention which includesthe second feature (2), the rotary member rotating device comprises aplurality of cam followers each of which is connected to a correspondingone of the rotary members; and at least one drive cam which has a camgroove engageable with each of the cam followers and which is rotatableabout an axis line to move the each cam follower and thereby rotate acorresponding one of the rotary members about the common axis line, atleast a portion of the cam groove having a width which permits the eachcam follower to be moved in a direction of the width, and thecircumferential position selecting device comprises a plurality ofcircumferential-direction pressing devices each of which selectivelypresses a corresponding one of the cam followers against each of a pairof opposed side surfaces of the cam groove. In the case where the camgroove of the drive cam includes an inclined portion which is inclinedrelative to the axis line of the cam, and a perpendicular portionextending in a direction perpendicular to the axis line, each of therotary members is rotated when the drive cam is rotated with the camfollower connected to said each rotary member being engaged with theinclined portion of the cam groove, and is stopped when the drive cam isrotated with the cam follower being engaged with the perpendicularportion of the cam groove. Therefore, two stop positions which arespaced from each other in the direction of rotation of the rotarymembers can be defined by employing a cam groove having a width whichpermits each cam follower to be moved in a direction of the width. Thatis, one of the two stop positions corresponds to the state in which eachcam follower is pressed against one of the two opposed side surfaces ofthe cam groove, and the other stop position corresponds to the state inwhich each cam follower is pressed against the other side surface of thecam groove. Thus, each rotary plate can be selectively positioned at oneof the two stop positions by pressing, using a rotating-direction orcircumferential-direction pressing device, the cam follower connected toeach rotary plate against a corresponding one of the two opposed sidesurfaces of the cam groove. Since in the present positioning apparatusthe plurality of circumferential positions are defined by providing adrive cam employed for rotating each rotary member, with a cam groovehaving a width which permits each cam follower to be moved in adirection of the width, the present apparatus can select one of theplurality of circumferential positions in a simple and low-cost manner.

(4) According to a fourth feature of the present invention whichincludes the second feature (2), the rotary member rotating devicecomprises a plurality of pairs of cam followers each pair of which areconnected to a corresponding one of the rotary members, respectively;and at least one drive cam which has a cam rib engageable with each pairof cam followers out of the pairs of cam followers and which isrotatable about an axis line to move the each pair of cam followers andthereby rotate a corresponding one of the rotary members about thecommon axis line, at least a portion of the cam rib of the drive camhaving a thickness which permits the each pair of cam followers to bemoved in a direction of the thickness, and the circumferential-positionselecting device comprises a plurality of circumferential-directionpressing devices each of which selectively presses each of the two camfollowers of a corresponding one pair of the pairs of cam followersagainst a corresponding one of a pair of opposite side surfaces of thecam rib. In the case where the cam rib of the drive cam includes aninclined portion which is inclined relative to the axis line of the cam,and a perpendicular portion extending in a direction perpendicular tothe axis line, each of the rotary members is rotated when the drive camis rotated with the pair of cam followers connected to said each rotarymember being engaged with the inclined portion of the cam rib, and isstopped when the drive cam is rotated with the pair of cam followersbeing engaged with the perpendicular portion of the cam rib. Therefore,two stop positions which are spaced from each other in the direction ofrotation of the rotary members can be defined by employing a cam ribhaving a width which permits each pair of cam followers to be moved in adirection of the width. That is, one of the two stop positionscorresponds to the state in which one of the two cam followers of eachpair is pressed against one of two opposite side surfaces of the camrib, and the other stop position corresponds to the state in which theother cam follower of each pair is pressed against the other sidesurface of the cam rib. Thus, each rotary plate can be selectivelypositioned at one of the two stop positions by pressing, using acircumferential-direction pressing device, one of the two cam followersconnected to each rotary plate against a corresponding one of the twoopposite side surfaces of the cam rib.

(5) According to a fifth feature of the present invention which includesany one of the first to fourth features (1) to (4), the positioningapparatus further comprises a stationary cam which has a cam grooveformed along a cylindrical surface having a center line on the commonaxis line; and a plurality of cam followers each of which is connectedto a corresponding one of the electronic component holder heads and isengageable with the cam groove of the stationary cam, at least a portionof the cam groove of the stationary cam having a width which permits theeach cam follower to be moved in a direction of the width, and the axialposition selecting device comprises a plurality of axial-directionpressing devices each of which selectively presses a corresponding oneof the cam followers against each of a pair of opposed side surfaces ofthe cam groove. In the present positioning apparatus, each of the camfollowers is pressed against one of the pair of opposed side surfaces ofthe cam groove and, when each of the rotary members is rotated, the camfollower connected to the EC holder head carried by said each rotarymember is moved along said one side surface of the cam groove. The pairof opposed side surfaces of the cam groove are spaced from each other inthe direction parallel to the common axis line, and the portion of thecam groove which has a width which permits each cam follower to be movedin a direction of the width, defines two axial positions which arespaced from each other in the direction parallel to the common axisline. Therefore, in the case where a portion of the cam groove whichcorresponds to a stop station has a width which permits each camfollower to be moved in a direction of the width, the presentpositioning apparatus can select one of the two axial positions at thestop station.

(6) According to a fifth feature of the present invention which includesthe fifth feature (5), the cam groove of the stationary cam includes aportion whose position in the direction parallel to the common axis linecontinuously changes. In the present positioning apparatus, when each ofthe cam followers is moved along the above-indicated portion of the camgroove, the EC holder head to which said each cam follower is connectedis moved in the direction of rotation of the rotary members while beingmoved in the direction parallel to the common axis line (hereinafter,referred to as the “axial direction”). Thus, the stop positions at whichthe EC holder head is stopped in the axial direction at one of aplurality of stop stations may differ from those at another stopstation. Each of the axial-direction pressing devices can press acorresponding one of the cam followers against a selected one of theopposed side surfaces of the cam groove, thereby selecting acorresponding one of the stop positions at each of the stop stations.For example, in the case where the present positioning apparatus isemployed by an EC mounting system which includes an EC supplying deviceand an EC mounting device and wherein the EC supplying and mountingdevices are provided at different height positions, respectively, theheight difference between the two devices can be compensated for bymoving each of the EC holder heads in the direction parallel to thecommon axis line which extends vertically. In the case where the presentpositioning apparatus is employed by an EC mounting system wherein an ECsupplying device and an EC mounting device are provided at the sameheight position or level, or wherein an EC supplying device and an ECmounting device can be moved up and down by respective elevating andlowering devices, respectively, the cam groove of the stationary camneed not include any portion whose position in the axial directioncontinuously changes, because there is no need to move each EC holderhead in the axial direction. In the latter case, the stationary cam mayhave the cam groove whose position in the axial direction does notchange at all. This is also the case with the EC holder head positioningapparatus wherein the stationary cam has a cam rib or ridge in place ofthe cam groove.

(7) According to a seventh feature of the present invention whichincludes any one of the first to fourth features (1) to (4), thepositioning apparatus further comprising a stationary cylindrical camwhich has a cam rib formed along a cylindrical surface having a centerline on the common axis line; and a plurality of pairs of cam followerseach pair of which are connected to a corresponding one of theelectronic component holder heads and is engageable with the cam rib ofthe stationary cam, at least a portion of the cam rib of the stationarycam having a thickness which permits the each pair of cam followers tobe moved in a direction of the thickness, and wherein the axial positionselecting device comprises a plurality of axial-direction pressingdevices each of which selectively presses each of the two cam followersof a corresponding one pair of the pairs of cam followers against acorresponding one of a pair of opposite side surfaces of the cam rib.The “thick” portion of the cam rib that is other than the “thin” portionthereof which has the thickness which permits each pair of cam followersto be moved in the direction of the thickness, may have a thicknesswhich is slightly greater than the distance between the two camfollowers in the direction of the thickness of the “thin” portion, sothat the two cam followers may engage the opposite side surfaces of thecam rib, respectively. In this case, each of the EC holder heads can bemoved along the cam rib without any rattling in the axial direction.Although only one of the two cam followers is pressed against acorresponding one of the two side surfaces of the cam rib by theaxial-direction pressing device, the two cam followers can be movedalong the cam rib while sandwiching the rib without any spaces providedtherebetween. The thickness of the “thin” portion of the cam rib issmaller than the distance between the two cam followers in the directionparallel to the direction of the thickness of the “thin” portion, i.e.,the axial direction. Along only the “thin” portion of the cam rib, thetwo cam followers are moved while only one of the two followers ispressed against, and engaged with, a corresponding one of the two sidesurfaces of the rib by the axial-direction pressing device. Thus,depending upon which one of the two cam followers is pressed against thecorresponding one of the two side surfaces of the cam rib, the presentpositioning apparatus can select, for each EC holder head, one of twoaxial positions which are distant from each other by a distance equal tothe difference between the thickness of the “thick” portion of the camrib and the thickness of the “thin” portion of the same.

(8) According to an eighth feature of the present invention whichincludes the seventh feature (7), the cam rib of the stationary camincludes a portion whose position in the direction parallel to thecommon axis line continuously changes. Like the positioning apparatus inaccordance with the above-indicated sixth feature (6), the presentpositioning apparatus can select, for each of a plurality of stopstations, one of a plurality of stop positions at which each of the ECholder heads is stopped in the axial direction.

(9) According to a ninth feature of the present invention which includesany one of the first and fifth to eight features (1), (5) to (8), therotary members are supported on a common, intermittently rotatable tablesuch that each of the rotary members is selectively movable to aplurality of positions thereof located on a circle having a center onthe common axis line, and wherein the circumferential position selectingdevice comprises a plurality of rotary member moving devices each ofwhich selectively moves a corresponding one of the rotary members to oneof the plurality of positions thereof.

(10) According to a tenth feature of the present invention whichincludes any one of the third to eight features (3) to (8), the at leastone drive cam comprises at least one concave globoidal cam having anouter circumferential surface which is defined by a locus which isdescribed by a circular arc having a center on the common axis line whenthe circular arc is rotated about a circular-arc axis line which isperpendicular to the common axis line and which is positioned relativeto the circular arc and the common axis line such that the circular arcis interposed between the circular-arc axis line and the common axisline. The outer circumferential surface of the concave globoidal camcontains the circular arc having the center on the common axis line.Therefore, when the globoidal cam which has an appropriate cam surfaceincluding a cam groove or a cam rib is rotated about an axis linethereof, the cam follower or followers which is or are engaged with thecam groove or rib is or are moved by the rotation of the cam, so therotary member to which the cam follower or followers is or are connectedis rotated about the common axis line over an angle corresponding to thelength of the cam in the direction of rotation of the rotary members.

(11) According to an eleventh feature of the present invention whichincludes any one of the third to tenth features (3) to (10), at leastone of the circumferential-direction pressing devices comprises afluid-pressure-operated cylinder device. In this case, thecircumferential-direction pressing devices can be produced at low cost.The fluid-pressure-operated cylinder device may be a double-acting aircylinder device.

(12) According to a twelfth feature of the present invention whichincludes any one of the fifth to eleventh features (5) to (11), at leastone of the axial-direction pressing devices comprises afluid-pressure-operated cylinder device. The fluid-pressure-operatedcylinder device may be a double-acting air cylinder device.

(13) According to a thirteenth feature of the present invention whichincludes any one of the fifth to twelfth features (5) to (12), thestationary cam includes a movable portion which is movable in thedirection parallel to the common axis line, and wherein the apparatusfurther comprises a movable portion moving device which moves themovable portion of the stationary cam and thereby moves at least one ofthe electronic component holder heads in the direction parallel to thecommon axis line. The movable portion of the stationary cam has a camgroove or a cam rib which provides part of the cam groove or rib of thestationary cam. As each of the rotary members is rotated, the camfollower or followers engages or engage the cam groove or rib of themovable portion. In this state, if the movable portion is moved by themovable portion moving device, the EC holder head carried on the rotarymember is moved in the axial direction.

(14) According to a fourteenth feature of the present invention whichincludes any one of the first to thirteenth features (1) to (13), eachof the electronic component holder heads comprises a sucking pipe whichsucks and holds, by vacuum, the electronic component.

(15) According to a fifteenth feature of the present invention, there isprovided an apparatus for selectively positioning at least oneelectronic component holder head for holding an electronic component, ata selected one of a plurality of positions of at least one station,comprising a holder head moving and stopping device which moves theelectronic component holder head along a predetermined movement path andstops the holder head at the at least one stop station on the movementpath; and at least one of (a) an on-path stop position selecting devicewhich selects, for the stop station, one of a plurality of on-path stoppositions on the movement path, so that the electronic component holderhead is stopped, and accordingly positioned, at the selected on-pathstop position as the selected one position, and (b) anintersecting-direction stop position selecting device which selects, forthe stop station, one of a plurality of intersecting-direction stoppositions which are spaced from each other in a direction intersectingthe movement path, so that the electronic component holder head isstopped, and accordingly positioned, at the selectedintersecting-direction stop position as the selected one position. Themovement path of the EC holder head is not limited to the circular pathemployed in the EC holder head positioning apparatus in accordance withthe first feature (1), but may be a curve other than the circular arc,or a straight line, or a composite of one or more curves and one or morestraight lines. For example, the EC holder head may be mounted on amovable member which is movable along a straight movement path and isstoppable at each of a plurality of stop stations on the movement path,and a plurality of stop positions may be provided for at least one ofthe stop stations. In this case, the present positioning apparatus canselect one of the stop positions so that the movable member or the ECholder head may be stopped at the selected stop position. A head movingdevice which moves the EC holder head may be provided on the movablemember. In this case, the positioning apparatus can select one of aplurality of stop positions, by operating the moving device to move thehead holder to a selected one of a plurality of positions on the movablemember. The movable member may support another or second movable memberwhich carries the EC holder head, such that the second movable member ismovable along a straight line perpendicular to the straight movementpath on a common plane. In this case, the EC holder head can be moved toany desired position on the common plane by the combination ofrespective movements of the two movable members. The positioningapparatus can select one of a plurality of stop positions at which theEC holder head is stopped, by moving one of the two movable members to aselected one of a plurality of stop positions therefor and moving theother movable member to a selected one of a plurality of stop positionstherefor. An EC holder head moving device may be mounted on the secondmovable member so as to move the EC holder head to a select one of aplurality of stop positions. In the case where the present positioningapparatus is employed by an EC mounting system including an EC supplyingdevice which utilizes a palette for supplying ECs, the EC holder headand the palette may be moved in respective directions perpendicular toeach other in a common plane, so that the EC holder head may pick up anEC accommodated in each of a number of EC accommodating pockets of thepalette. Alternatively, each of the head and the palette may be moved inboth the two directions, so that the head may pick up the ECs from thepalette. Moreover, one of the head and the palette may be moved in onlyone direction and the other may be moved in both the two directions, sothat the head may pick up the ECs from the palette. In either case, thepositioning apparatus can select one of the stop positions at each ofwhich the EC holder head is stoppable, thereby selecting one of aplurality of EC pick-up positions at each of which the EC holder headcan pick up an EC from the palette. This arrangement contributes toreducing the cumulative distances of movement of the palette. Theintersecting direction in which the stop positions are spaced from eachother may be any direction intersecting the movement path of the ECholder head, for example, a vertical direction. In the case where the ECholder head is supported on a movable member which is movable along themovement path, such that the holder head is movable on the movablemember in a direction perpendicular to the movement path, theintersecting direction may be a direction which is perpendicular to boththe movement path and the direction in which the EC holder head ismovable on the movable member, or a direction which is perpendicular tothe movement path and is parallel to the direction of movement of the ECholder head on the movable member. The present EC holder headpositioning apparatus can select, for a stop station, one of a pluralityof stop positions at each of which the EC holder head is stoppable whenthe head is moved along the movement path which may contain a straightline and/or a curve. Therefore, irrespective of the kind of the ECmounting apparatus which employs the present positioning apparatus, thepositioning apparatus contributes to improving the EC mountingefficiency of the mounting apparatus.

(16) According to a sixteenth feature of the present invention whichincludes the fifteenth feature (15), the positioning apparatus furthercomprising a movable member which supports the electronic componentholder head such that the holder head is movable in a directionintersecting the movement path and which is movable along the movementpath; a stationary cam having a cam groove extending along the movementpath; a cam follower which is connected to the movable member such thatthe cam follower is movable with the holder head and which is engageablewith the cam groove of the stationary cam, at least a portion of the camgroove having a width which permits the cam follower to be moved in adirection of the width, and wherein the intersecting-directionstop-position selecting device comprises an intersecting-directionpressing device which selectively presses the cam follower against eachof a pair of opposed side surfaces of the cam groove. Theintersecting-direction pressing device may comprise afluid-pressure-actuated cylinder device, such as a double-acting aircylinder device.

(17) According to a seventeenth feature of the present invention whichincludes the fifteenth feature (15), the positioning apparatus furthercomprises a movable member which supports the electronic componentholder head such that the holder head is movable in a directionintersecting the movement path and which is movable along the movementpath; a stationary cam having a cam rib extending along the movementpath; a pair of cam followers which are connected to the movable membersuch that the pair of cam followers are movable with the holder head andwhich are engageable with the cam rib of the stationary cam, at least aportion of the cam rib having a thickness which permits the pair of camfollowers to be moved in a direction of the thickness, and wherein theintersecting-direction stop-position selecting device comprises anintersecting-direction pressing device which selectively presses each ofthe two cam followers of the pair against a corresponding one of a pairof opposite side surfaces of the cam rib. The intersecting-directionpressing device may comprise a fluid-pressure-actuated cylinder device,such as a double-acting air cylinder device.

(18) According to an eighteenth feature of the present invention whichincludes any one of the fifteenth to seventeenth features (15) to (17),the electronic component holder head comprises a sucking pipe whichsucks and holds, by vacuum, the electronic component.

(19) According to a nineteenth feature of the present invention, thereis provided an apparatus for transferring an electronic component,comprising at least one electronic component holder head which holds anelectronic component; a holder head moving device which moves theelectronic component holder head along a predetermined movement path;and a path selecting device which selects, as at least a portion of themovement path, one of a plurality of selectable paths which havedifferent positions, respectively, in a direction intersecting theportion of the movement path, so that the electronic component holderhead is moved along the movement path including the selected oneselectable path. In the case where a stop station is provided on theabove-indicated portion of the movement path, the present ECtransferring apparatus can select, for the stop station, one of aplurality of stop positions at each of which the EC holder head isstoppable. However, this feature is not essential to the present ECtransferring apparatus. For example, the EC holder head is notessentially required to be stopped at an image taking station where animage of an EC held by the holder head is taken for confirming the kindof the EC and/or detecting the possible position errors of the EC heldby the holder head. That is, it is possible to take an image of the ECbeing moved. However, if the kind of one EC held by the EC holder headis different from that of another EC held by the holder head, thedistance between an image taking device and the surface of each EC whoseimage is to be taken by the image taking device at the image takingstation may not coincide with the focal length of the image takingdevice. In this case, the above distance may be so changed as tocoincide with the focal length, by changing at least a portion of themovement path along which the EC holder head is moved. The present ECtransferring apparatus may be advantageously used in this way, as well.The movement path may be a circular arc, a straight line, a curve otherthan the circular arc, or a composite of those lines. The intersectingdirection may be a direction perpendicular to the above portion of themovement path, such as a vertical direction.

(20) According to a twentieth feature of the present invention whichincludes the nineteenth feature (19), the transferring apparatus furthercomprises an image taking device which is provided in association withthe portion of the movement path and which takes an image of theelectronic component held by the electronic component holder head.

(21) According to a twenty-first feature of the present invention whichincludes the twentieth feature (20), the image taking device comprises aline sensor which takes, as the image of the electronic component, a setof respective images of contiguous linear portions of the component asthe component is moved. The line sensor comprises a number of imagepick-up elements which are arranged in a straight array extending in adirection intersecting the direction in which an EC is moved, and takesan image of a linear portion of the EC at regular intervals of time asthe EC is moved. Thus, the line sensor takes, as the image of the EC, aset of respective images of the contiguous linear portions of the EC asthe EC is moved. When the EC finishes passing by the line sensor, theline sensor finishes taking the entire image of the EC. Thus, atwo-dimensional image of the EC is obtained by the combination of theiterative linear-image taking of the line sensor and the movement of theEC held by the EC holder head.

(22) According to a twenty-second feature of the present invention whichincludes the twentieth feature (20), the image taking device comprises ahigh-speed camera which emits, when the electric component held by theelectronic component holder head passes, a single flashlight toward thecomponent for so short a time that an amount of movement of thecomponent during the time is negligible, and which takes the image ofthe component exposed to the single flashlight. For example, in the casewhere the high-speed camera has a stroboscope, the stroboscope emits astrong flashlight toward an EC which is passing by the camera, so thatthe camera takes an image of the EC. Although the EC is moving, thecamera can take an image of the EC, as if the EC were stopped, byemploying a very high shutter speed or a very short light-emitting time.

(23) According to a twenty-third feature of the present invention, thereis provided a system for mounting an electronic component on an object,comprising an electronic component holder head positioning apparatusaccording to the first feature (1); an electronic component supplydevice which is provided at a first one of a plurality of stop stationscomprising the at least one stop station and which supplies anelectronic component to each of the electronic component holder heads sothat the each holder head holds the electronic component; and an objectsupporting and positioning device which is provided at a second one ofthe stop stations and which supports and positions an object on whichthe electronic component held by the each holder head is to be mounted.

(24) According to a twenty-fourth feature of the present invention, themounting system further comprises an image taking device which isprovided at a third one of the stop stations and which takes an image ofthe electronic component held by the each holder head.

(25) According to a twenty-fifth feature of the present invention, thereis a system for mounting an electronic component on an object,comprising an electronic component holder head positioning apparatusaccording to the feature (15); an electronic component supply devicewhich is provided at a first one of a plurality of stop stationscomprising the at least one stop station and which supplies anelectronic component to each of the electronic component holder heads sothat the each holder head holds the electronic component; and an objectsupporting and positioning device which is provided at a second one ofthe stop stations and which supports and positions an object on whichthe electronic component held by the each holder head is to be mounted.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and optional objects, features, advantages and technical andindustrial significance of this invention will be better understood byreading the following detailed description of presently preferredembodiments of the invention, when considered in connection with theaccompanying drawings, in which:

FIG. 1 is a plan view schematically showing an electronic componentmounting system according to one embodiment of the present invention,including an electronic component transferring and mounting apparatusequipped with one embodiment of an electronic component transferringdevice of the invention;

FIG. 2 is a front elevational view in cross section of the electroniccomponent transferring and mounting apparatus of FIG. 1;

FIG. 3 is a plan view of the present electronic component transferringand mounting apparatus;

FIG. 4 is a front elevational view in cross section showing rotaryplates supported by a stationary shaft in the present transferring andmounting apparatus;

FIG. 5 is a view indicating three positions at which component holderheads are stopped in the transferring and mounting apparatus;

FIG. 6 is a front elevational view in cross section showing one of thecomponent holder heads in the transferring and mounting apparatus;

FIG. 7 is a front elevational view in cross section of the componentholder head of FIG. 6 placed in an operating state in which a sleeve andan inner shaft are disconnected from each other;

FIG. 8 is a bottom plan view showing a head elevating and loweringdevice and a stationary cylindrical cam in the transferring and mountingapparatus;

FIG. 9 is a block diagram illustrating a part of a control device forcontrolling the present electronic component mounting system, which partrelates to the present invention;

FIG. 10 is a timing chart indicating a relationship between the rotatingangle of the twelve rotary plates and the time in the transferring andmounting apparatus;

FIGS. 11A-1, 11A-2 and 11A-3 are graphs showing changes in the position,rotating speed and acceleration or deceleration of the rotary plate inthe present transferring and mounting apparatus, in the vicinity of astop position of the rotary plate;

FIGS. 11B-1, 11B-2 and 11B-3 are graphs corresponding to those of FIGS.11A, in a conventional transferring and mounting apparatus;

FIG. 12 is a graph for explaining reduction in the time required for onepitch of rotary movement of the rotary plate to the stop position in thepresent transferring and mounting apparatus;

FIG. 13 is a front elevational view in cross section of an electroniccomponent transferring and mounting apparatus in an electronic componentmounting system constructed according to another embodiment of thisinvention;

FIG. 14 is a plan view partly in cross section showing the transferringand mounting apparatus of FIG. 13, taken at a vertical position in whichcam follower rollers of rotary plates engage concave globoidal cams;

FIG. 15 is a view schematically showing a cam groove in one of theconcave globoidal cams of FIG. 14, and the corresponding cam followerroller which is selectively brought into engagement with two sidesurfaces of a non-lead portion of the cam groove;

FIG. 16 is a view showing the cam groove of FIG. 15 in a developedstate;

FIG. 17 is a view showing a cam groove in a stationary cylindrical camused in the electronic component transferring and mounting apparatus ofFIG. 13;

FIG. 18 is a plan view showing a portion of the apparatus of FIG. 13 inwhich there are provided stop position changing air cylinders, stopposition changing valves, height position changing valves, first andsecond valve switching devices for the stop position changing valves,and valve switching devices for the height position changing valves;

FIG. 19 is a front elevational view showing the stop position changingvalve, height position changing valve, first stop position changingvalve switching device, and their vicinities in the apparatus of FIG.13;

FIG. 20 is a front elevational view in cross section showing the stopposition changing valve, height position changing valve, height positionchanging switching device and their vicinities in the present apparatus;

FIG. 21 is a block diagram showing a part of a control device forcontrolling the electronic component mounting system including thetransferring and mounting apparatus of FIG. 13, which part relates tothe present invention;

FIGS. 22A-22C are views for explaining a change in the component suckingposition where a cartridge support is fed in a forward direction, in theapparatus of FIG. 13;

FIGS. 23A-23D are views for explaining a change in the component suckingposition where the cartridge support is fed in a reverse direction, inthe apparatus of FIG. 13;

FIG. 24 is a view for explaining changes in the height position of thecomponent holder head and the vertical head stroke in the apparatus ofFIG. 13;

FIG. 25 is a front elevational view in cross section showing atransferring and mounting apparatus in an electronic component mountingsystem constructed according to a further embodiment of this invention;

FIG. 26 is a plan view showing the transferring and mounting apparatusof FIG. 25;

FIG. 27 is a front elevational view in cross section showing one ofconcave globoidal cams in the transferring and mounting apparatus ofFIG. 25;

FIG. 28 is a view showing cam grooves of the concave globoidal cam ofFIG. 27, in a developed state;

FIG. 29 is a cross sectional view taken along line 29—29 of FIG. 28,showing the cam groove of the concave globoidal cam;

FIG. 30 is a view for explaining an offset of center lines of wide andnarrow portions of the cam groove of the concave globoidal cam of FIG.27;

FIG. 31 is a timing chart indicating a relationship between the rotatingangle of fifteen rotary plates and the time in the apparatus of FIG. 25;

FIGS. 32A-32D are graphs showing changes in the torque of the concavegloboidal cam at the stop position and its vicinity of the rotary platein the apparatus of FIG. 25;

FIG. 33 is a plan view schematically showing means for preventingreleasing of a cam follower in an electronic component transferringapparatus according to a still further embodiment of the invention;

FIG. 34 is a plan view schematically showing means for preventing thereleasing of the cam follower in an electronic component transferringapparatus according to a yet further embodiment of this invention;

FIG. 35 is a view schematically showing an example of cam followerreleasing preventing means provided in an apparatus in which a concavegloboidal cam is used in combination with a cylindrical cam;

FIG. 36 is a timing chart indicating a relationship between the rotatingangle of the twelve rotary plates and the time in the transferring andmounting apparatus of FIG. 13;

FIG. 37 is a view for explaining changes in the height position of acomponent holder head of an electronic component transferring apparatusaccording to another embodiment of this invention;

FIG. 38 is a view for explaining changes in the height position of acomponent holder head of an electronic component transferring apparatusaccording to yet another embodiment of this invention;

FIG. 39 is a view for explaining changes in the height position of acomponent holder head of an electronic component transferring apparatusaccording to yet another embodiment of this invention;

FIG. 40 is a view for explaining the state in which an elevator platewhich carries a component holder head is engaged with a cam rib of astationary cam which is employed by a component holder head positioningdevice as part of an electronic component transferring and mountingapparatus according to yet another embodiment of this invention;

FIG. 41 is a view of an essential portion of an electronic componentmounting system which includes an intermittently rotatable table and aplurality of component holder heads which are supported by the table andeach of which sequentially sucks up an EC and mounts the EC as the tableis intermittently rotated, wherein the mounting system additionallyincludes a circumferential-position selecting device or an on-path stopposition selecting device as part of a component holder head positioningapparatus;

FIG. 42 is a view of an essential portion of an electronic componentmounting system which includes a movable member which is movable along astraight movement path, and a component holder head which is supportedby the movable member such that the holder head is movable with themovable member so as to suck up an EC and mounts the EC, wherein themounting system additionally includes an intersecting-direction stopposition selecting device as part of a component holder head positioningapparatus, or a path selecting device as part of an electronic componenttransferring apparatus;

FIG. 43 is a perspective view of the head elevating and lowering deviceand the stationary cylindrical cam of FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIGS. 1-12, there will be described an electroniccomponent mounting system including an electronic component transferringand mounting apparatus 12 which is equipped with an electronic componenttransferring device constructed according to one embodiment of thepresent invention.

In FIG. 1, reference numeral 10 denotes a base on which are mounted theelectronic component transferring and mounting apparatus 12, anelectronic component supply device 14, and a workpiece supporting andpositioning device in the form of a board supporting and positioningdevice 16. The electronic component supply device 14 includes acartridge support block 20 which carries a multiplicity of componentsupply cartridges 22 (hereinafter referred to as “cartridges 22) suchthat the component supply portions of the cartridges 22 are arrangedalong a straight line.

The cartridge support block 20 is provided with a nut (not shown)engaging a feed screw 24. When the feed screw 24 is rotated by a drivesource in the form of a cartridge feed servomotor 26, the cartridgesupport block 20 is fed in an X-axis direction while it is guided byguide members in the form of a pair of straight guide rails 28. Thus,one of the cartridges 22 which are arranged in the X-axis direction isbrought to a predetermined component supply position. The nut, feedscrew 24 and cartridge feed servomotor 26 constitute a major portion ofa cartridge feeding device 30 for feeding the cartridges 22 in theX-axis direction.

The board supporting and positioning device 16 is disposed at a levellower than that of the cartridges 22 of the electronic component supplydevice 14. This device 16 includes an X-axis table 34 movable in theX-axis direction, and a Y-axis table 36 which is mounted on the X-axistable 34 and which is movable in a Y-axis direction which isperpendicular to the X-axis direction in a horizontal plane. The Y-axistable 36 has a board holding device (not shown) mounted thereon toposition a workpiece in the form of a printed-circuit board 38. TheX-axis table 34 is moved in the X-axis direction while it is guided byguide members in the form of straight guide rails 44 when a feed screw40 is rotated by a drive source in the form of an X-axis driveservomotor 42. The Y-axis table 36 is moved in the Y-axis directionwhile it is guided by guide members in the form of straight guide rails50 when a feed screw 46 is rotated by a drive source in the form of aY-axis drive servomotor 48. With the X-axis table 34 and the Y-axistable 36 being moved in the horizontal plane, the printed-circuit board38 is positioned such that a multiplicity of component mounting portionsof the board 38 are sequentially aligned with a predetermined componentmounting position. The X-axis table 34 extends below the electroniccomponent transferring and mounting apparatus 12, and a portion of thetable 34 is located below the cartridges 22. The printed-circuit board38 is loaded and unloaded onto and from the board holding device of theboard supporting and positioning apparatus 16, in the X-axis direction.

The electronic component transferring and mounting apparatus 12 isdisposed above the electronic component supply device 14 and the boardsupporting and positioning device 16. The apparatus 12 is adapted toreceive the electronic components from the electronic component supplydevice 14 and transfer the electronic components onto theprinted-circuit board 38, namely, mount the electronic components on theboard 38. Thus, the apparatus 12 serves not only as an electroniccomponent transferring device, but also as an electronic componentmounting device.

Referring to FIG. 2, the electronic component transferring and mountingapparatus 12 has a main body including a frame 60, which is supported bysupport members (not shown) fixed to the base 10 indicated above. Thatis, the frame 60 is disposed above the base 10. The frame 60 has amounting structure 62 in the form of a box having a U-shape in crosssection, and a support plate 64 which extend between and are fixed to apair of side walls of the mounting structure 62.

A support shaft in the form of a stationary shaft 66 having a circularcross sectional shape is fixed at its upper end by the support plate 64of the frame 60, and extends downwards through an opening 69 formedthrough a bottom wall 67 of the mounting structure 62. The lower endportion of the stationary shaft 66 is located outside and below themounting structure 62, and is fixed at its lower end by a support plate68 secured to the base 10. As shown in FIGS. 2 and 3, twelve rotarymembers in the form of rotary plates 70 are fixed to respective pairs ofbearings 72, such that the rotary plates 70 are rotatable about an axisof the stationary shaft 66. This axis of the stationary shaft 66 servesas a common axis about which the rotary plates 70 are rotatable.

The bearings 72 consists of two arrays 74 of bearings which are fixedlydisposed on the stationary shaft 66 such that the two arrays 74 arespaced apart from each other in the axial direction of the shaft 66.Each of these two arrays 74 consists of twelve bearings 74 which arearranged in the axial direction, namely, superposed on each other in astack. The twelve rotary plates 70 are associated with respective pairsof support arms 76 fixed thereto. Each pair of support arms 76 are fixedto and supported by the corresponding pair of bearings 72 which belongto the two arrays 74, respectively. All the pairs of bearings 72corresponding to the respective pairs of support arms 76 of the twelverotary members 70 have the same distance therebetween in the axialdirection of the stationary shaft 66.

As shown in FIG. 4, each of the support arms 76 consists of an annularfitting 78, and a radial arm 80 which extends from a portion of thecircumference of the annular fitting 78 in a radial outward direction ofthe annular fitting 78. Each pair of support arms 76 has a connectingportion 82 which connects the two radial arms 80. The connecting portion82 of each pair of support arms 76 and the end portions of the radialarms 80 connected to the connecting portion 82 are fixed to thecorresponding rotary plate 70, while the annular fittings 78 are fittedon respective outer casings 84 of the corresponding pair of bearings 72and are fixed to the outer casings 84 by a plurality of bolts. Thetwelve pairs of support arms 76 have different axial positions at whichthe arms 76 are fixed to the respective rotary plates 70. Accordingly,the support arms 76 do not interfere with each other, even though therotary plates 70 have the same position with respect to the stationaryshaft 66 in the axial direction of the shaft 66. In this arrangement,the twelve rotary plates 70 are rotatable about the common axis, namely,about the axis of the stationary shaft 66, such that all the rotaryplates 70 maintain a predetermined position or height in the axialdirection of the stationary shaft 66. The pair of radial arms 80 and theconnecting portion 82 are provided with a rib 86, which has a thinnedfixed end portion on the side of the stationary shaft 66, as indicatedby broken lines in FIG. 3. The thickness of the thinned fixed endportion of the rib 86 decreases in a radial direction toward thestationary shaft 66, so that the fixed end portions of the adjacent ribs86 and the adjacent radial arms 80 do not interfere with each other.Each rotary plate 70 extends downwards through the opening 69 formedthrough the bottom wall 67 of the frame 60, and the lower end portion ofthe rotary plate 70 is located below the bottom wall 67.

As shown in FIG. 2, a cam follower in the form of a cam follower roller88 is attached to a radial end of each rotary plate 70 remote from thestationary shaft 66, such that the roller 88 is rotatable about ahorizontal axis extending in a radial direction of the stationary shaft66. As shown in FIG. 3, the rollers 88 of the twelve rotary plates 70are held in rolling engagement in cam grooves 92 a, 92 b, 92 c, 92 dformed in four concave globoidal cams 90 a, 90 b, 90 c, 90 d which arerotatably mounted on the frame 60. In the interest of brevity andsimplification, the twelve rotary plates 70 are shown in FIG. 3 aspositioned relative to each other such that the rotary plates 70 areevenly or equi-angularly spaced apart from each other about thestationary shaft 66.

The four concave globoidal cams 90 a, 90 b, 90 c, 90 d have respectiveouter circumferential surfaces 93 a, 93 b, 93 c, 93 d. The outercircumferential surface 93 is defined by a locus which is to bedescribed by a circular arc having a center at the axis of thestationary shaft 66 when the circular arc is rotated about an axis whichis located such that the circular arc is interposed between this axisand the axis of the stationary shaft 66 and which is perpendicular tothe axis of the stationary shaft 66. The axis about which the circulararc is rotated to describe the above-indicated locus defining thecircumferential surface 93 is an axis of a rotary shaft 94 of theconcave globoidal cam 90, which will be described. The four concavegloboidal cams 90 a, 90 b, 90 c, 90 d are disposed symmetrically withrespect to the axis of the stationary shaft 66, such that lines ofintersection of the outer circumferential surfaces 93 a, 93 b, 93 c, 93d of the cams 90 a, 90 b, 90 c, 90 d with a plane (horizontal plane)including the axes of the cams 90 and perpendicular to the axis of thestationary shaft 66 cooperate to define a substantially continuouscircle which has a center at the axis of the stationary shaft 66. Thecam grooves 92 a, 92 b, 92 c, 92 d formed in the outer circumferentialsurfaces 93 a, 93 b, 93 c, 93 d are substantially connected to eachother.

The concave globoidal cams 90 a, 90 b, 90 c, 90 d are fixedly mounted onrespective rotary shafts 94 a, 94 b, 94 c, 94 d, as shown in FIG. 3. Therotary shafts 94 are rotatably supported by respective pairs of brackets96 a, 96 b, 96 c, 96 d fixed to the mounting structure 62 of the frame60. The four concave globoidal cams 90 a-90 d have respective pairs ofbevel gears 98 a, 100 a, 98 b, 100 b, 98 c, 100 c, 98 d, 10 d. The bevelgears 98, 100 of each globoidal cam 90 are formed integrally andcoaxially with the cam 90, at the axially opposite ends. The bevel gears98, 100 of the adjacent concave globoidal cams 90 a-90 d are held inmeshing engagement with each other.

The rotary shaft 94 a to which the concave globoidal cam 90 a isattached has a larger axial length than the other rotary shafts 94 b-94d, and is rotatably supported also by another bracket 104 fixed to theframe 60, as shown in FIG. 3. At the free end of the rotary shaft 94 a,there is fixed a timing pulley 106, which is connected by a timing belt112 to a timing pulley 110 fixed to an output shaft of a main drivesource in the form of an electrically operated main drive servomotor108. When the rotary shaft 94 a is rotated by the main drive servomotor108, the four concave globoidal cams 90 are contemporaneously rotated insynchronization with each other, with the bevel gears 98 a-98 d meshingwith each other, so that the twelve rotary plates 70 are rotated aboutthe stationary shaft 66 or held stationary, as described below.

In the present electronic component transferring and mounting apparatus12, the rotary plates 70 are stopped at a component sucking station, animage taking station and a component mounting station. In thesestations, there are set a component sucking position, an image takingposition and a component mounting position, respectively, as shown inFIG. 5. At the component sucking position, the apparatus 12 receives theelectronic components from the electronic component supply device 14,which is located on the base 60, at a position in the vicinity of thecomponent sucking position. A CCD (charged-coupled device) camera 114(FIG. 9) is located on the base 10, at a position corresponding to thethe image taking position, while the board supporting and positioningdevice 16 is located on the base 10, at a position corresponding to thecomponent mounting position.

The concave globoidal cam 90 a is located at a position corresponding tothe component mounting position, and the concave globoidal cam 90 c islocated at a position corresponding to the component sucking position,while the concave globoidal cam 90 d is located at a positioncorresponding to the image taking position. The cam grooves 92 a, 92 c,92 d of the cams 90 a, 90 c, 90 d are formed or shaped so that therotary plates 70 (cam follower rollers 88) are held stopped at thecomponent sucking and mounting positions and the image taking position,and are decelerated and accelerated during movements thereof toward andfrom those three positions, and such that the rotary plates 70 arerotated at a predetermined constant angular velocity when thecorresponding cam follower rollers 88 are moving into and from the camgrooves 92 a, 92 c, 92 d. Each of the cam grooves 92 a, 92 c, 92 d ofthe concave globoidal cams 90 a, 90 c, 90 d has an inclined portionhaving a lead angle with respect to a plane perpendicular to the axis ofthe rotary shaft 94 a, 94 c, 94 d, and a non-lead portion perpendicularto that axis. The inclined portion includes a curved section and astraight section. The cam groove 92 b of the concave globoidal cam 90 bhas only a straight inclined portion having a lead angle with respect toa plane perpendicular to the axis of the rotary shaft 94 b. This leadangle is determined to permit the rotary plates 70 to be rotated at theabove-indicated constant angular velocity.

It is noted that a component container (not shown) is provided in acomponent discarding area between the component mounting and suckingstations of the apparatus 12. Described more specifically, the componentcontainer is provided along a circular arc path of component holderheads 120 carried by the rotary plates 70, and are located below thecomponent holder heads 120, so that the component container accommodateselectronic components which are discarded from the component holderheads 120 during rotation of the rotary plates 70 from the componentmounting station to the component sucking station. Namely, theelectronic components which have been sucked up by the component holderheads 120 are not mounted on the printed-circuit board 38 and discardedinto the component container, if the components have not been adequatelypositioned with respect to sucking nozzles of the heads 120, that is, ifthe components held by the heads 120 are dislocated to such an extentthat the position of the components cannot be corrected. The componentsare also discarded if the kinds of the components which have been heldby the heads 120 are different from those of the components that shouldbe mounted.

Each of the twelve rotary plates 70 carries a component holder head 120,as shown in FIG. 2. Each rotary plate 70 has guide members in the formof a pair of guide blocks 122 fixed thereto such that the guide blocks122 are spaced apart from each other in the vertical direction. Amovable member in the form of a vertical slide 124 engages the guideblocks 122 such that the vertical slide 124 is vertically slidablymovable. To an upper part of the vertical slide 124, there is attached acam follower in the form of a cam follower roller 126 such that theroller 126 is rotatable about an axis extending in a radial direction ofthe stationary shaft 66. To a lower part of the vertical slide 124,there is attached the component holder head 120.

A stationary cylindrical cam 128 is fixed to the underside (lowersurface) of the bottom wall 67 of the frame 60, in coaxial relationshipwith the stationary shaft 66. The cam follower roller 126 indicatedabove is held in rolling engagement with a cam groove 130 formed in theinner circumferential surface of the cylindrical cam 128. The cam groove130 has a height varying portion whose height (in the axial direction ofthe shaft 66) gradually varies in the circumferential direction of thecam 128, and a level portion whose height is held constant in thecircumferential direction. The cam groove 130 is formed so that eachcomponent holder head. 120 is placed in its upper end position when therotary plate 70 is located at the component sucking position, and isplaced in its lower end position when the rotary plate 70 is located atthe component mounting position, and so that the component holder head120 is moved in a horizontal plane when the rotary plate 70 is rotatedaround each of the component sucking and mounting positions and theimage taking position. In the present arrangement, the vertical slide124 is moved up and down to move the component holder head 120 in thevertical direction when the cam follower roller 126 is moved in rollingcontact with the height varying portion of the cam groove 130, with therotary plate 70 being rotated with the cam follower roller 126.

As shown in FIG. 6, a bracket 136 is fixed to the lower end portion ofthe vertical slide 124, and a sleeve or hollow shaft 138 is supported bythe bracket 136 via bearings 140, 142 such that the sleeve 138 isrotatable relative to the bracket 136 and is axially immovable relativeto the bracket 136. An inner shaft 144 is fitted in the sleeve 138 suchthat the inner shaft 144 is rotatable and is axially immovable relativeto the sleeve 138. A holder portion 146 which is generally U-shaped incross section is fixed to the lower end of the sleeve 138 locatedoutside the bracket 136. The holder portion 146 has a pair of side walls148, 150, and a support shaft 152 which is fixed at its opposite ends tothe side walls 148, 150. The support shaft 152 carries a cylindricalnozzle holder 154 rotatably mounted thereon.

The nozzle holder 154 has six nozzle engaging radial holes 156 which areequi-angularly spaced from each other in the circumferential directionof the support shaft 152. The radial holes 156 accommodate respectivecylindrical suction nozzles 158 such that the nozzles 158 are axiallymovable in the radial holes 156 and are not rotatable relative to thenozzle holder 154. The suction nozzles 158 are biased in a radiallyoutward direction of the nozzle holder 154 by biasing means in the formof elastic members in the form of respective compression coil springs160 accommodated in the radial holes 156. Rotation of each suctionnozzle 158 in the radial hole 156 and axial movement of the suctionnozzle 158 out of the radial hole 156 are prevented by engagement of apin (not shown) provided on the suction nozzles 158 with the oppositeends of a corresponding groove (not shown) formed in the nozzle holder154. The six suction nozzles 158 are provided for sucking up electroniccomponents 164 of respective different sizes. The six suction nozzles158 have respective suction tubes 162 having respective differentdiameters. Each of the suction nozzles 158 has a reflector plate 163.The diameter of the reflector plates 163 of the suction nozzles 158whose suction tubes 162 have a comparatively small diameter is smallerthan that of the reflector plates 163 of the suction nozzles 158 whosesuction tubes 162 have a comparatively large diameter. The suction tubes162 of the six suction nozzles 158 have the same length, so that thefree ends of the suction tubes 162 lie on a circle having a center onthe axis of rotation of the cylindrical nozzle holder 154.

The six suction nozzles 158 are selectively placed in an operatingposition by rotation of the nozzle holder 154, as described below. Whena selected one of the suction nozzles 158 is in the operating position,its axis extends in the vertical direction, and the free end of itssuction tube 162 is located right below the axis of the support shaft152. The axis of the suction nozzle 158 placed in the operating positionis aligned with the axis of the sleeve 138.

The suction nozzles 158 are adapted to hold the electronic component 164by air suction. As shown in FIG. 6, passages 168, 170, 172, 174, 176,177 are formed through the nozzle holder 154, support shaft 152, sidewall 150, inner shaft 144, sleeve 138 and bracket 136, respectively. Aswitching device 178 is attached to the bracket 136, so that the suctionnozzle 158 placed in the operating position is communicated selectivelywith a vacuum source (not shown) or the atmosphere by an operation ofthe switching device 178. The vacuum source is connected through aconduit (not shown) to a passage (not shown) formed through thestationary shaft 66, and this passage is connected through a rotaryvalve (not shown) to the twelve switching devices 178 through respectivehoses. The rotary valve is disposed at a position of the stationaryshaft 66, which is lower than the bearing arrays 74. A rotary motion ofa valve drive servomotor (not shown) disposed on the support plate 68 istransmitted to the rotary valve through timing pulley and belt, so thatthe rotary valve is held operated at the same angular velocity as thatof the constant-velocity movement of the rotary plate 70, whereby theswitching device 178 is held connected to the vacuum source. When therotary plate 70 is stopped, the switching device 178 and the rotaryvalve are rotated by a small angle relative to each other. This relativerotation is permitted by the elastic deformation of the hose.

Each switching device 178 has a solenoid-operated switch valve operatedfor selective communication of the suction nozzle 158 with the vacuumsource or the atmosphere, so that the electronic component 164 is suckedup by the suction tube 158 or released therefrom. The passage 170 formedthrough the support shaft 152 is connected to the passage 168 whichcommunicates with the suction nozzle 158 placed in the operatingposition.

A gear 180 is rotatably mounted on the support shaft 152, and is fixedto the nozzle holder 154 by a connecting member in the form of a pin 182so that the nozzle holder 154 is rotated with the gear 180. The gear 180meshes with a gear 186 fixed to a support shaft 184 which is rotatablyattached to the side wall 148 of the holder portion 146. The gears 180,186 have the same diameter. The gear 186 has an integrally formed bevelgear 188, while the inner shaft 144 has a bevel gear 190 integrallyformed at its lower end. The bevel gears 188, 190 mesh with each other,and have the same diameter. The upper end portion of the inner shaft 144projects upwards from the sleeve 138, and is connected through aconnecting member 196 to an output shaft 194 of a nozzlerotating/selecting servomotor 192. The inner shaft 144 is axiallymovable and is not rotatable relative to the connecting member 196. Thenozzle rotating/selecting servomotor 192 is bidirectionally operated ata suitable speed, and an angle of rotation of the output shaft 194 isdetected by an encoder (not shown).

The supplying of electric energy from a power source to thesolenoid-operated valves as the switching devices 178 and the nozzlerotating/selecting servomotors 192 may be achieved by using a commonslip ring. However, in the present embodiment, the electric energy issupplied by a no-contact electricity supplying device disclosed in,e.g., U.S. Pat. No. 5,588,195. The no-contact electricity supplyingdevice includes twelve electricity suppliers and twelve electricityreceivers for the twelve switching devices 178 and the twelveservomotors 192, respectively. The electricity suppliers are provided onthe stationary shaft 66, and include respective supply-side coils eachconnected to the power source. The electricity receivers includerespective receiver-side coils which are opposed to the supply-sidecoils with small clearances therebetween, and are rotated at a constantspeed together with the above-indicated rotary valve (not shown)employed for the supplying of vacuum, by the above-indicated valve driveservomotor (not shown). The receiver-side coils are connected viaconductive lines to the solenoid-operated valves 178 and the nozzlerotating/selecting servomotors 192, so as to receive the electric energysupplied from the electricity suppliers.

The connecting member 196 takes the form of a sleeve which engages theoutput shaft 194 and is connected to the output shaft 194 through aconnecting member in the form of a pin 198 such that the sleeve 196 isnot rotatable and axially immovable relative to the output shaft 194.The connecting member 196 has two cutouts 206 formed on diametricallyopposite portions. These cutouts 206 extend in the axial direction ofthe connecting member 196 and are open in the lower end face of theconnecting member 196. The upper end portion of the inner shaft 144 isfitted in the connecting member 196 such that the inner shaft 144 isaxially movable relative to the connecting member 196. The inner shaft144 has a pin 208 extending diametrically through its upper end portionsuch that the opposite end portions of the pin 208 project outwardly ofthe inner shaft 144. These opposite end portions of the pin 208 engagethe respective cutouts 206 such that the opposite end portions of thepin 206 are movable in the cutouts 208 in the axial direction of theinner shaft 144. With the pin 206 and the cutouts 206 engaging eachother, a rotary motion of the nozzle rotating and selecting servomotor192 is transmitted to the inner shaft 144 through the connecting member196. Thus, the pin 208 and the cutouts 206 serve as a first 5 engagingmember and a second engaging member, respectively, which engage eachother and cooperate to permit the connecting member 196 and the innershaft 144 to be connected to each other such that the connecting member196 and inner shaft 144 are axially movable relative to each other andare not rotatable relative to each other.

A drive member 202 in the form of a ring is fitted on the inner shaft144 such that the drive member 202 is axially movable relative to theinner shaft 144. The drive member 202 includes a portion which isconcentrically and fixedly fitted in the lower end of the connectingmember 196 so as to close the lower open ends of the cutouts 206. Thedrive member 202 has a toothed peripheral portion 200 formed by sixgrooves, which are formed through the thickness of the drive member 202such that the grooves are equi-angularly arranged in the circumferentialdirection of the drive member 202 and are open in the radially outwarddirection.

The vertical slide 124 carries a motor support in the form of anelevator 210 on which the nozzle rotating/selecting servomotor 192 ismounted. The elevator 210 is generally U-shaped in cross section, andincludes two opposed side wall 212, 216 which partly defines theU-shape. The elevator 210 has a guide member in the form of a guideblock 214 fixed to the side wall 212, and is vertically slidable on thevertical slide 124 through the guide block 214. To an outer surface ofthe other side wall 216, there is attached a cam follower in the form ofa cam follower roller 218, which is rotatable about an axis extending ina radial direction of the stationary shaft 66. The side wall 216 has acylindrical engaging boss 220 formed on its lower end face. The engagingboss 220 has a relatively small diameter.

The elevator 210 is biased upwards by biasing means in the form of anelastic member in the form of a compression coil spring 224 interposedbetween the drive member 202 and the upper end of the sleeve 138 whichis located above the bracket 136. That is, the elevator 210 is biased bythe spring 224 in a vertical direction away from the sleeve 138. Anupward movement of the elevator 210 under the biasing action of thecompression coil spring 224 is limited by abutting contact of the drivemember 202 with the pin 208 fixed to the inner sleeve 144. In otherwords, the upper stroke end position of the elevator 210 is establishedby this abutting contact of the drive member 202 with the pin 208. Adriven member 232 is fixed to the upper end portion of the sleeve 138.The driven member 232 includes an annular portion 234 fixedly fitted onthe sleeve 138. The annular portion 234 has a radial extension whichextends radially outwardly in a direction away from the vertical slide124 and which has an engaging cutout 238.

The driven member 232 further includes an arm portion 240 extendingupwards from the annular portion 234. The arm portion 240 has teeth 242formed on an inner surface thereof facing the inner shaft 144. The teeth242 provides part of an internally gear, which cooperates with thetoothed peripheral portion 200 of the drive member 202 to constitute aclaw clutch. When the elevator 210 is placed in its upper stroke endposition under the upward biasing action of the compression coil spring224, the toothed peripheral portion 200 of the drive member 202 is heldin meshing engagement with the teeth 242 of the arm portion 240 of thedriven member 232, such that the toothed peripheral portion 200 and theteeth 242 are movable relative to each other in the axial direction ofthe sleeve 138 and are not rotatable relative to each other, whereby thesleeve 138 and the inner shaft 144 are not rotatable relative to eachother. In this condition, the engaging boss 220 provided on the elevator210 is aligned with the engaging cutout 238 formed through the drivenmember 232, in the circumferential direction of the sleeve 138, and theengaging boss 220 is engageable with the cutout 238 when the elevator210 is moved down. This position in which the boss 220 is engageablewith the cutout 238 will be referred to as an “original circumferentialposition” of the sleeve 138 and the component holder head 120. In thisoriginal circumferential position, the horizontal axis of the supportshaft 152 rotatably supporting the nozzle holder 154 extends in a radialdirection of the stationary shaft 66 (axis of rotation of the rotaryplate 70), which is parallel to the plane of the rotary plate 70.

A stationary nozzle selecting cam 248 is located in an area which isbetween the component discarding area and the component sucking stationand in which the rotary plates 70 are rotated at the predeterminedconstant velocity while the component holder heads 120 are moved in ahorizontal plane maintaining a constant height. The nozzle selecting cam248 has a cam surface 250 which is elongated in the rotating directionof the rotary plates 70, along a circular arc having a center at theaxis of the stationary shaft 66. The cam surface 250 consists of adownwardly inclined region, a level region, and an upwardly inclinedregion, which are arranged in the rotating direction of the rotaryplates 70. The downwardly inclined region is inclined downwards in therotating direction of the rotary plates 70, namely, in the directionfrom the upwardly inclined region toward the level region. The levelregion extends from the downstream or lowest end of the downwardlyinclined region, at the same level or height as the lowest position atthe downward end of the downwardly inclined region. The upwardlyinclined region extends from the downstream end of the level regionremote from the downwardly inclined region, and is inclined upwards inthe rotating direction of the rotary plates 70, namely, in the directionfrom the level region toward the downwardly inclined region. As the camfollower roller 218 is moved in rolling contact with the downwardlyinclined region of the cam surface 250, the elevator 210 is moveddownwards. The elevator 210 is held level while the cam follower roller218 is moved in rolling contact with the level region. As the roller 218is moved in rolling contact with the upwardly inclined region, theelevator 210 is permitted to be moved upwards. The height of the nozzleselecting cam 248 is determined so that the downwardly inclined regionof the cam surface 250 is engageable with the cam follower roller 218when the elevator 210 is placed in its upper stoke end position. Theinitial portion of the downwardly inclined region is shaped to have apart-cylindrical surface, for facilitating the engagement with theroller 218. The elevator 210 is placed in its lower stroke end positionwhile the roller 218 is in rolling contact with the level region of thecam surface 250 of the cam 248.

While a certain rotary plate 70 is moved from the image taking positiontoward the component mounting position, the nozzle rotating/selectingservomotor 192 is actuated in a controlled manner to correct apositioning error of the electronic component 164 held by the componentholder head 120, more specifically, to remove a deviation of the angularposition of the electronic component 164 about the axis of the suctiontube 162. While the rotary plate 70 is located between the image takingposition and the component mounting position, the sleeve 138 and theinner shaft 144 are connected to each other through engagement of theteeth 242 of the driven member 232 with the toothed peripheral portion200 of the drive member 200, as shown in FIG. 6, so that a rotary motionof the nozzle rotating/selecting servomotor 192 is transmitted to thesleeve 138 through the connecting member 196, drive member 202 anddriven member 232. A rotary motion of the sleeve 138 causes a rotarymotion of the suction nozzle 158 placed in the operating position, aboutits axis, whereby the electronic component 164 held by suction on theend face of the suction tube 162 is rotated about the axis of thesuction tube 162, by an amount suitable to remove the angularpositioning error of the component 164. This amount of rotation of thecomponent 164 is calculated on the basis of angular positioning dataobtained from an output of the CCD camera 144 at the image takingposition.

It is noted that the inner shaft 144 is rotated with the sleeve 138,whereby the meshing position of the two bevel gears 188, 190 remainsunchanged, so that the bevel gear 188 remains stationary, and the nozzleholder 154 is prevented from being rotated about the axis of the supportshaft 152, to thereby prevent changing the suction nozzle 158 placed inthe operating position.

As a result of rotation of the sleeve 138, the engaging cutout 238formed in the driven member 232 is offset from the engaging boss 220provided on the elevator 210, in the rotating direction of the sleeve138. After the electronic component 164 is mounted on theprinted-circuit board 38 and while the rotary plate 70 is rotated towardthe component discarding area, the sleeve 138 is rotated in thedirection opposite to the direction of the rotation effected to removethe angular positioning error of the component 164, by the same amountas in the removal of the angular positioning error, so that the engagingcutout 238 is brought into alignment with the engaging boss 220 in thecircumferential or rotating direction of the sleeve 138.

While the rotary plate 70 is rotated from the component discharging areatoward the component sucking station, with the component holder head 120being moved at the constant velocity while maintaining the same height,the cam follower roller 218 is brought into engagement with the camsurface 250 of the nozzle rotating/selecting cam 248. Described indetail, the roller 218 initially contacts the downwardly inclined regionof the cam surface 250, pushing down the elevator 210 against thebiasing force of the compression coil spring 224. As a result, the teeth242 of the driven member 232 is disengaged from the toothed peripheralportion 200 of the drive member 202, and the sleeve 138 is disengagedfrom the inner shaft 144, as shown in FIG. 7. Before the driven member232 and the drive member 202 are completely disengaged from each other,the engaging boss 220 on the elevator 210 is moved into the engagingcutout 238 formed in the driven member 232, whereby the sleeve 138 isprevented from rotating and is held in the original circumferentialposition. The sleeve 138 is returned to the original circumferentialposition before the cam follower roller 218 is brought into contact withthe cam surface 250, that is, before an operation to select the suctionnozzle 158 is initiated. Consequently, the engaging boss 220 can bemoved into the engaging cutout 238 to prevent rotation of the sleeve 138when the elevator 210 is moved down by the cam follower roller 218.While the rotary plate 70 is rotated after the driven member 232 and thedrive member 202 are disengaged from each other, the roller 218 is heldin contact with the level region of the cam surface 250, so that thesleeve 138 and the inner shaft 144 are held disengaged from each otherwith the driven and drive members 232, 202 being held disengaged fromeach other.

When it is desired to change the suction nozzle 158 used to hold theelectronic component 146, the nozzle rotating/selecting servomotor 192is actuated in the condition of FIG. 7. As a result, only the innershaft 144 is rotated, and a rotary motion of the inner shaft 144 istransmitted to the nozzle holder 154 through the bevel gears 188, 190and the gears 180, 182, so that the nozzle holder 154 is rotated aboutthe axis of the support shaft 152 to place a desired one of the sixsuction nozzles 158 in the operating position. The suction nozzle 158currently placed in the operating position can be determined by theangle of and direction of rotation of the inner shaft 144, and the kindof the suction nozzle 158 that should be used for holding the nextelectronic component 164 can be determined according to a componentmounting program which is formulated to mount various electroniccomponents 164 in a predetermined order on the printed-circuit board 38.The angle and direction of rotation of the servomotor 192 can bedetermined based on the determined kind of suction nozzle 158 currentlyplaced in the operating position and the determined kind of theelectronic component 164 to be mounted next. Thus, the appropriatesuction nozzle 158 is brought into the operating position by anoperation of the servomotor 192. The direction of rotation of theservomotor 192 is determined so as to reduce the angle of rotation ofthe nozzle holder 154 required to select the desired suction nozzle 158.

Since the bevel gears 189, 186 have the same diameter while the gears180, 182 have the same diameter, the nozzle holder 154 is rotated by thesame angle as the inner shaft 144. The teeth of the bevel gears 188, 190and gears 180, 186 are accurately shaped to minimize an amount of gearbacklash, so that the desired suction nozzle 158 can be positioned atthe operating position with high accuracy by rotation of the servomotor192 by the determined angle.

When only the inner shaft 144 is rotated, the sleeve 138 is preventedfrom rotating by engagement of the engaging boss and cutout 220, 238, sothat the sleeve 138 is not rotated through friction between the sleeve138 and the inner shaft 144, that is, so that the nozzle holder 154 isrotated about the horizontal axis which extends in the radial directionof the stationary shaft 66 and which is parallel to the plane of therotary plate 70.

During an operation to select the desired suction nozzle 158, theelevator 210 is held in its lower stroke end position with the camfollower roller 218 held in rolling contact with the level region of thecam surface 250 of the cam 248, so that the inner shaft 144 and thesleeve 138 are held disengaged from each other. After the desiredsuction nozzle 158 has been selected, the roller 218 is brought intocontact with the upwardly inclined region of the cam surface 250. As therotary plate 70 is further rotated, the elevator 210 is graduallyelevated by the compression coil spring 224. As a result, the teeth 242of the driven member 232 are brought into engagement with the toothedperipheral portion 200 of the drive member 202, and the engaging boss220 is disengaged from the engaging cutout 238, whereby the sleeve 138and the inner shaft 144 are connected to each other for simultaneousrotation, and the sleeve 138 is disengaged from the elevator 210. Theteeth 242 are brought into engagement with the toothed peripheralportion 202 before the boss 220 is disengaged from the cutout 2238.Since the sleeve 138 is prevented from rotating during rotation of theinner shaft 144 to select the suction nozzle 158, the teeth 242 canengage the toothed peripheral portion 200 of the drive member 202 whichhas been rotated during the operation to select the suction nozzle 158.Since the bevel gears 188, 190 have the same diameter and the gears 180,186 have the same diameter, the nozzle holder 154 is rotated by the sameangle as the inner shaft 144 during a nozzle selecting operation toselect the suction nozzle 158. The toothed peripheral portion 200consists of six grooves. The angular phase of the toothed peripheralportion 200 in which the teeth 200 engage the portion 200 after thenozzle selecting operation is offset from that before the nozzleselecting operation, by the angle of rotation of the nozzle holder 154during this operation.

The selection of the desired suction nozzle 158 as described above iseffected before the electronic component 164 is sucked up by thecomponent holder head 120. When the rotary plate 70 reaches thecomponent sucking position, the desired suction nozzle 158 for holdingthe next component 164 has been placed in the operating position. Atthis time, the head 120 is placed in the original circumferentialposition. When the angular position of the electronic component 164 asheld by the suction nozzle 158 is corrected, the head 120 is rotatedfrom the original circumferential position in the forward or reversedirection.

As described above, the nozzle rotating/selecting servomotor 192provided on the component holder head 120 is used as the drive sourcefor selecting the desired suction nozzle 158 and for removing an angularpositioning error of the component 164 held by the head 120. Thisarrangement makes it possible to effect the above operations duringrotation of the component holder head 120 about the stationary shaft 66,and allows for a relatively long time in which these operations shouldbe completed. Accordingly, the present arrangement is effective toreduce the angular velocity upon rotation of the suction nozzle 158about its axis, and prevent or minimize the vibration which would takeplace during the operations to select the suction nozzle 158 and correctthe angular position of the component 164. The present arrangement isalso effective to increase the maximum angle of rotation of the nozzleholder 154. Further, since the servomotor 192 is used not only as thedrive source for selecting the suction nozzle 158 but also as the drivesource for correcting the angular position of the component 164, theseoperations can both be performed during movement of the head 120 aboutthe stationary shaft 66, whereby the electronic component transferringand mounting apparatus 12 can be simplified in construction, andmanufactured with a reduced weight and at a reduced cost.

At two positions corresponding to the component sucking and mountingpositions of the frame 60, there are disposed two head elevating andlowering devices 260 as shown in FIGS. 2 and 8. More precisely, thesefigures show the head elevating and lowering device 260 disposed at theposition corresponding to the component mounting position. FIG. 8 is abottom plan view of the device 260 as seen from under the frame 60.Since the two head elevating and lower devices 260 have the sameconstruction, the device 260 at the position corresponding to the thecomponent mounting position of the frame 60 will be explained.

The stationary cylindrical cam 128 has an engaging groove 262 formed ata circumferential position thereof corresponding to the componentmounting position. This groove 262 is open in the inner circumferentialsurface and the upper and lower surfaces of the cylindrical cam 128, asshown in FIGS. 2 and 8. The cam 128 further has a radial opening 264,which is formed through an upper part of a radially outer portion of thecam 128 in the radial direction, for communication with the engaginggroove 262. A vertically movable member 266 is vertically movablyreceived in the groove 262. The cam 128 further has a guide member inthe form of a straight guide rail 268 formed on the bottom wall of thegroove 262 in the vertical direction (in the axial direction of the cam128). On the other hand, a pair of guide blocks 270 are fixed to thevertically movable member 266. These guide blocks 270 slidably engagethe guide rail 268.

A lower portion of the vertically movable member 266 has acircumferential dimension (as measured in the circumferential directionof the cylindrical cam 128), which is determined to provide a smallclearance between the lower portion and the inner surfaces of the groove262, for permitting the vertically movable member 266 to move verticallyin the groove 262. A groove 272 is formed through this lower portion ofthe vertically movable member 266, such that the groove 272 is open inthe inner surface of the member 266 corresponding to the innercircumferential surface of the cylindrical cam 128, and extends in ahorizontal plane in a direction parallel to a tangent line at acircumferential point of the cam groove 130 corresponding to thecomponent mounting position.

The vertically movable member 266 has an upper portion whosecircumferential dimension is smaller than that of the lower portiondescribed above. This upper portion is pivotably connected at an upperpart thereof to a forked end portion of a pivotal member in the form ofa lever 276 through a shaft member in the form of a pin 277. The lever276 extends through the radial opening 264 and projects radiallyoutwardly from the outer circumferential surface of the cam 128. Thelever 276 is supported at an intermediate portion thereof by a supportportion 280 of a support member 278 through a bearing 282 such that thesupport member 278 is moved relative to the lever 276 in thelongitudinal direction of the lever 276. The bearing 282 has two supportpins 284 formed on two side surfaces thereof parallel to thelongitudinal direction of the lever 276, such that the support pins 284extend perpendicularly to the longitudinal direction of the lever 276,as shown in FIG. 8. These support pins 284 function as a shaft portionwhich rotatably engages the support portion 280 of the support member278, so that the lever 276 is pivotable together with the bearing 282,about the axis of the support pins 284.

As shown in FIG. 8, the support member 282 has an arm portion 288extending horizontally from the support portion 280 into the interior ofthe frame 60 through an elongate hole 286 formed through the frame 60.The arm portion 288 carries a nut 292 fixed at its free end within theframe 60. The nut 292 engages a feed screw 294, which is rotated by adrive source in the form of a head stroke adjusting servomotor 296 formoving the support member 270 in the longitudinal direction of the lever276. A movement of the support member 278 in the longitudinal directionof the lever 276 causes a longitudinal movement of the bearing 282 andthe support pins 284 relative to the lever 276, whereby the pivotingaxis of the lever 276 is changed in the longitudinal direction of thelever 276, to thereby change the vertical stroke of the verticallymovable member 266. Thus, the feed screw 294 and the servomotor 296constitute a major portion of a device for changing the vertical strokeof the vertically movable member 266. A guide block 298 is fixed to thesupport portion 280. This guide block 298 is in sliding contact with aguide rail 299 fixed to the frame 60, so that the support member 278 isguided by the guide block 298 and the guide rail 299.

As shown in FIG. 2, a generally L-shaped lever 300 is rotatablysupported by a shaft 302 fixed to the frame 60. The lever 300 has an arm303 whose free end is pivotally connected to an upper end portion of aconnecting member in the form of a rod 304 through a shaft member in theform of a pin 306. The upper end portion of the rod 304 is movablerelative to the pin 306 in the axial direction of the pin 306. The rod304 extends through an elongate hole 305 formed through the mountingstructure 62, and the lower end of the rod 304 is pivotally connectedthrough a pin 308 to an end portion of the lever 276 remote from the endportion connected to the vertically movable member 266.

The generally L-shaped lever 300 has another arm 312 which carries a camfollower roller 314 pivotably attached at its free end portion. Thelever 300 is biased by biasing means in the form of an elastic member inthe form of a tension coil spring 316 so that the cam follower roller314 is held in rolling contact with a cam surface 320 of a headelevating and lowering cam 318 which is rotatably attached to the frame60.

The head elevating and lowering cam 318 is supported by a support shaft322 which is rotatably supported by the frame 60. As shown in FIG. 3, atiming pulley 324 is fixedly mounted on the support shaft 322, and thetiming pulley 324 is connected through the timing belt 112 to the timingpulley 110 fixed to the output shaft of the main drive servomotor 108.Thus, the head elevating and lowering cam 318 is driven by the sameservomotor 108 as used for driving the concave globoidal cams 90 a-90 d.The diameter of the timing pulley 324 is determined so that the cam 318is rotated through 360° for a component mounting time interval equal toa time interval at which the rotary plates 70 are successively stoppedat the component mounting position.

While FIG. 2 shows that the head elevating and lowering cam 318 has acam surface 320 which has a circular shape, the cam 318 actually has aheart-like shape in cross section, so that a rotary motion of the cam318 causes the lever 300 to be pivoted to vertically move the rod 304for thereby pivoting the lever 276 so as to vertically move thevertically movable member 266. Since the rod 304 and the verticallymovable member 266 are connected to the opposite ends of the lever 276on the opposite sides of the support pins 284, the member 266 is moveddown while the rod 304 is moved up, and vice versa. The lowermost anduppermost positions of the rod 304 are determined by the profile of thecam surface 320. Described more specifically, the lowermost position ofthe rod 304 is adjusted by adjusting the axial position of the rod 304so that the groove 272 formed through the vertically movable member 266is aligned or contiguous with the cam groove 130 in the cylindrical cam128 in the vertical direction, so as to form a horizontal groove, and sothat the lever 276 has a horizontal attitude parallel to the feed screw294 and the guide rail 299 when the rod 304 is placed in the lowermostposition. The uppermost position of the vertically movable member 266 isdetermined by the lowermost position of the rod 304 determined asdescribed above. In the uppermost position of the vertically movablemember 266, this member 266 cooperates with the adjacent portions of thecam groove 130 to hold the component holder head 120 at the uppermostposition for a predetermined time. To mount the electronic component 164on the printed-circuit board 38 when the rotary plate 70 is located atthe component mounting position of the cylindrical cam 128, thevertically movable member 266 disposed at the position corresponding tothe component mounting position is first lowered from the uppermostposition to the lowermost position and then elevated back to theuppermost position. The member 266 is held at the uppermost position atthe positions other than the component mounting position.

As is apparent from the above description, the lever 276 is parallel tothe guide rails 299 for guiding the support member 278 when thevertically movable member 266 is placed in the uppermost position withthe rod 304 moved to the lowermost position. In this condition, thesupport member 278 is moved as needed, in the direction parallel to theguide rails 299, to change the position of the pivoting axis of thelever 276. Thus, the operating stroke of the vertically movable member266 can be changed by changing the lowermost position of the member 266,without changing the uppermost position of the member 266.

The electronic component transferring and mounting apparatus 12 iscontrolled by a control device 330 illustrated in the block diagram ofFIG. 9. The control device 330 is constituted principally by a computer340 incorporating a central processing unit (CPU) 332, a read-onlymemory (ROM) 334, a random-access memory (RAM) 336, and a bus 338connecting these elements 332, 334, 336. To the bus 338, there isconnected an input interface 342 which receives an output of the CCDcamera 114. Also connected to the bus 338 is an output interface 344which is connected to the cartridge feed servomotor 26, X-axis driveservomotor 42, Y-axis drive servomotor 48, main drive servomotor 108,nozzle rotating/selecting servomotors 192 and head stroke adjustingservomotor 296, through respective driver circuits 346, 348, 350, 352,354 and 356. The ROM 334 stores various control programs such as thosefor sucking up the electronic component 164, taking an image of thecomponent 164 and mounting the component 164 on the printed-circuitboard 38.

When the electronic components 164 are mounted on the printed-circuitboard 38 in the electronic component mounting system including thetransferring and mounting apparatus 12, the four concave globoidal cams90 a-90 d are concurrently rotated by the main drive servomotor 108 torotate and stop the twelve rotary plates 70 such that the acceleration,deceleration, constant-velocity movement and stopping of the rotaryplates 70 are effected independently of each other. The rotary plates 70are stopped at the component sucking position, image taking position andcomponent mounting position, so that the electronic components 164 aresucked up by the heads 120 at the component sucking position, subjectedto an image taking operation at the image taking position, and mountedon the board 38 by the heads 120 at the component mounting position.

The operation for the component holder head 120 to hold the electroniccomponent 164 will be first explained.

When a given rotary plate 70 is rotated about the stationary shaft 66toward the component sucking position, the cam follower roller 126 inrolling contact with the cam groove 130 is moved into the groove 272formed through the vertically movable member 266 received in the groove262 formed in the cylindrical cam 128. The roller 126 is moved from thecam groove 130 into the groove 272 before the rotary motion of therotary plate 70 to the component sucking position is completed. Afterthe cam follower roller 126 has been moved into the groove 272 andbefore the rotary plate 70 is stopped at the component sucking position,a downward movement of the vertically movable member 266 from theuppermost position is initiated, whereby the roller 126 is lowered asthe member 266 is lowered. As a result of the downward movement of theroller 126, the vertical slide 124 is lowered, and the component holderhead 120 is accordingly lowered. Thus, a movement of the head 120 aboutthe stationary shaft 66 and a downward movement of the head 120 areeffected contemporaneously.

As a result of the downward movement of the head 120, the suction tube162 of the suction nozzle 158 is brought into contact with the uppersurface of the electronic component 164, and the switching device 178 isswitched to a position in which the electronic component 164 isattracted under suction to the lower end of the suction tube 162. Therotary plate 70 has been stopped at the component mounting position whenthe suction tube 162 is brought into contact with the electroniccomponent 164, so that the component 164 can be attracted to the suctiontube 162 with high reliability. After the component 164 is sucked up bythe head 120, the vertically movable member 266 is moved up, and the camfollower roller 126 is accordingly moved up, whereby the vertical slide124 is elevated to elevate the head 120, so that the component 164sucked up by the suction nozzle 158 is picked up from the cartridge 22.

After the component 164 is picked up from the cartridge 22 by the head120, the rotation of the rotary plate 70 about the stationary shaft 66is resumed before the vertically movable member 266 has reached itsuppermost position and before the groove 272 has been aligned with thecam groove 130. The roller 126 is elevated in rolling contact with thegroove 272 in the member 266, and is moved from the groove 272 into thecam groove 130 of the cylindrical cam 128 immediately after the member266 has reached the uppermost position. Thus, the head 120 issimultaneously elevated and rotated after the component 164 is sucked upfrom the cartridge 22.

Upon sucking of the electronic component 164, the vertical stroke of thehead 120 is changed as needed if necessary, depending upon the heightdimension or level of the upper surface of the electronic component 164.The upper surfaces of the electronic components 164 may have differentlevels depending upon the height dimensions of the components 164, wherea component accommodating portion of a component holder tape in thecomponent supply cartridge 22 is supported by a body of the cartridge 22which is located below the component accommodating portion.

The component holder tape has a multiplicity of component accommodatingrecesses in which the components 164 are accommodated. These recessesare closed by an upper covering tape to prevent removal of thecomponents 164 from the recesses. The thickness of the component holdertape increases with an increase in the height dimension of thecomponents 164. However, the height of the tape guiding surface of thebody of the cartridge 22 is constant, so that the level of the uppersurface of the component 164 is raised as the height dimension of thecomponent 164 increases. Consequently, the vertical stroke of thecomponent holder head 120 should be reduced with an increase in theheight dimension of the electronic component 164 to be sucked up by thehead 120. This adjustment of the vertical operating stroke of the head120 is effected before the component 164 is sucked up by the suctionnozzle 158. To this end, the head stroke adjusting servomotor 296 isactuated to move the support member 278 in the longitudinal direction ofthe lever 276, for thereby changing the position of the pivoting axis ofthe lever 27.6. For reliable attraction of the component 164 to thesuction tube 162 of the suction nozzle 158, the vertical stroke of thehead 120 is accurately determined on the basis of not only the distancebetween the lower end face of the suction tube 162 of the head 120 andthe upper surface of the component 164, but also a height error of thecomponent 164 due to a positioning error associated with the electroniccomponent supply device 12. An excessive downward movement of thesuction nozzle 158 may be accommodated or absorbed by compression of thecoil spring 160 biasing the suction nozzle 158.

After the electronic component 164 has been held by the head 120, therotary plate 70 is rotated to the image taking position, at which therotary plate 70 is stopped so that the component 164 sucked up by thesuction nozzle 158 is held stationary. In this condition, an image ofthe component 164 is taken by the CCD camera 114. On the basis of anoutput of the CCD camera 114, an angular position error, and X-axis andY-axis position errors of the component 164 are calculated. The angularposition of the component 164 is adjusted to remove the angular positionerror before the rotary plate 70 has reached the component mountingposition. To this end, the nozzle rotating/selecting servomotor 192 isactuated to rotate the sleeve 138 and the inner shaft 144 so that thesuction nozzle 158 placed in the operating position is rotated about itsaxis to rotate the component 164 by an angle suitable to remove theangular position error.

Before an operation to mount the electronic component 164 on theprinted-circuit board 38, an image of a fiducial mark provided on theboard 38 is taken to calculate X-axis and Y-axis positioning errors ofthe board 38 for each of the component mounting locations. When theelectronic components 164 are mounted on the printed-circuit board 38,the board 38 is moved in the X-axis and Y-axis directions, so that thelocations at which the electronic components 164 are mounted are rightunder the component holder head 120 located at the component mountingposition. On the basis of the calculated positioning errors of the board38 and the X-axis and Y-axis position errors of the component 164, thedistances of movement of the board 38 in the X-axis and Y-axisdirections are adjusted to mount the component 164 at the nominal X-axisand Y-axis positions on the board 38.

When the rotary plate 70 is rotated toward the component mountingposition, the cam follower roller 126 is moved from the cam groove 130of the cylindrical cam 128 into the groove 272 in the vertically movablemember 266 at the component mounting position. After the roller 126 hasentered the groove 272 and before the rotary plate 70 has reached thecomponent mounting position, a downward movement of the verticallymovable member 266 is initiated to lower the component holder head 120while the head 120 is rotated toward the component mounting position.The rotary plate 70 has been stopped at the component mounting positionbefore the component 164 is mounted on the printed-circuit board 38.Namely, the head 120 is further lowered to mount the component 164 atthe predetermined point on the board 38 after the rotary plate 70 hasreached the component mounting position.

The vertical operating stroke of the head 120 is changed depending uponthe height dimension of the component 164 when the component 164 ismounted on the board 38. The stroke of the head 120 is reduced as theheight dimension of the component 164 increases. Precisely, the strokeof the head 120 should accommodate positioning errors such asdimensional and positioning errors in the manufacture of the boardsupporting and positioning device 16, for example, so that theelectronic components 164 can be accurately mounted on the board 38.After the component 164 has been placed at the predetermined point onthe board 38, the switching device 178 is switched to a position to stopthe application of a vacuum pressure to the suction nozzle 158, wherebythe component 164 is released from the suction nozzle 158. After thecomponent 164 is mounted on the board 38, the vertically movable member266 is elevated to elevate the head 120. In this case, too, the rotationof the rotary plate 70 is resumed before the member 266 has reached theuppermost position, so that the roller 127 is elevated while it is movedin rolling contact with the groove 272. Immediately after the verticallymovable member 266 has reached the uppermost position, the roller 126 ismoved into the cam groove 120, and the rotary plate 70 is rotated towardthe component sucking position.

While the rotary plate 70 is rotated from the component mountingposition toward the component sucking position, the sleeve 138 isrotated in the direction opposite to the direction in which the sleeve138 was rotated to correct the angular position of the component 164before mounting thereof on the board 38. The amount of rotation of thesleeve 138 at this time is the same as that for correcting the angularposition of the component 164, so that the sleeve 138 and the head 120are returned to their original circumferential position.

In the event of some error at the component sucking position, thevertical stroke of the vertically movable member 266 at the componentmounting position is reduced to a smallest value to avoid drawbacksdescribed below. Such component sucking error may be a failure of thesuction nozzle 158 to pick up the component 164, an erroneous operationof picking up of the wrong component 164, or an excessively large errorof the angular position of the sucked component 164 that cannot beremoved. In such event, the vertical stroke of the head 120 is reducedto a smallest value to prevent abutting contact of the suction nozzle162 of the suction nozzle 158 (without the component 164 being attractedthereto) or the wrong component 164 with the printed-circuit board 38when the head 120 is lowered to the lowermost position at the componentmounting position. In this case, the switching device 178 is notswitched at the component mounting position, and the vacuum pressure iskept applied to the suction nozzle 158, so that the component 164 iscarried by the head 120 to the component discarding area. In thecomponent discarding area, the switching device 178 is actuated to stopthe application of the vacuum pressure to the suction nozzle 158, fordiscarding the component 164 into the component container. Where thesuction nozzle 158 fails to pick up the electronic component 164, thisfailure may be detected on the basis of the image taken at the imagetaking position. In this case, the switching device 178 is actuated tostop the application of the vacuum pressure to the suction nozzle 158.

When the rotary plate 70 is further rotated, the cam follower roller 218provided on the elevator 210 is brought into engagement with the camsurface 250 of the nozzle selecting cam 248, so that the sleeve 138 isdisconnected from the inner shaft 144. If the kind of the suction nozzle158 is changed, the nozzle rotating/selecting servomotor 192 is operatedto rotate the nozzle holder 154 so that the suction nozzle 158 to beused next is brought into the operating position.

As described above, there are three stop positions at which the rotaryplate 70 is stopped. Between the component sucking position and theimage taking position, and between the image taking position and thecomponent mounting position, the rotary plate 70 is rotated through 90°,with acceleration, constant-velocity movement and deceleration. Betweenthe component mounting and sucking positions, the rotary plate 70 isrotated through 180° at a constant velocity. The timing chart of FIG. 10shows a relationship between the time and the angle of rotation of eachof the twelve rotary plates 70. In FIG. 10, “T” represents the timerequired for each rotary plate 70 to be rotated through 360°, and thistime is taken along the abscissa, with a graduation unit being equal toT/12 in view of the twelve rotary plates 70. On the other hand, theangle of rotation of the rotary plate 70 is taken along the ordinate,with a graduation unit being equal to an angular spacing pitch of thetwelve rotary plates 70 or heads 120. The time-angle relationship ofeach rotary plate 70 is expressed by a line having a straight portion,an upwardly curved or convex portion and a downwardly curved or concaveportion. The straight portion indicates the constant-velocity movementof the rotary plate 70. The convex portion indicates the deceleration ofthe rotary plate 70, while the concave portion indicates theacceleration of the rotary plate 70. It will be understood from thetiming chart of FIG. 10 that the individual rotary plates 70 are rotatedindependently of each other so that the nine rotary plates 70 can berotated about the stationary shaft 66 while the three rotary plates 70are held stopped at the component sucking, image taking and componentmounting positions, for the corresponding heads 120 to pick up and mountthe components 164, and for the CCD camera 114 to take an image of thecomponent 164.

The present electronic component transferring and mounting apparatus 12having the twelve component holder heads 12 has only three stoppositions, so that the required acceleration and deceleration values ofthe heads 120 can be reduced, as compared with those in the conventionalcomponent transferring device in which a plurality of component holderheads are carried by an intermittently rotated rotary table. Suppose theconventional rotary table carries twelve heads arranged along a circlewhose diameter is the same as that of the circle along which the heads120 are rotated, and suppose the time required for one full rotation ofthe conventional rotary table is the same as the time T in the presentapparatus 12, the required acceleration and deceleration values of theheads 120 in the present apparatus 12 are smaller than those in theconventional apparatus using the conventional rotary table. The reasonfor this will be described below.

Each of FIGS. 11A-1 through 11A-3 shows four adjacent blocks of FIG. 10according to the present embodiment, wherein a stop position of thecomponent holder head 120 is indicated in the vicinity of anintersection of two mutually perpendicular partition lines of theblocks. Each of FIGS. 11B-1 through 11B-3 shows the corresponding fouradjacent blocks according to the conventional apparatus. Two-dot chainlines (inclined straight lines) in FIGS. 11A-1 and 11B-1 indicate acontinuous movement of the component holder head 120 as indicated in theother four adjacent blocks of FIG. 10 which do not include a stopposition. When the head 120 in the present apparatus 12 is stopped atthe stop position at the end of a rotary movement thereof correspondingto the angular spacing pitch of the rotary plates 70 or heads 120, thehead 120 is initially moved at a constant velocity which is representedby the gradient or angle of inclination of the inclined straight two-dotchain line in FIG. 11A-1. Then, the head 120 is accelerated as indicatedby an initial portion of a solid line in FIG. 11A-1 which initialportion is located above the two-dot chain line. By this acceleration,the amount of angular displacement of the head 120 is larger than thatby the constant-velocity movement represented by the two-dot chainlines. Finally, the head 120 is decelerated and eventually stopped atthe stop position. Thus, the acceleration is effected to compensate fora sum of a time corresponding to a difference between the averagevelocity during the deceleration period and the constant velocityrepresented by the two-dot chain lines, and a time during which the head120 is held stopped as represented by a horizontal portion of the solidlines. When a rotary motion of the head 120 is resumed after stopping atthe stop position, the sequence of events (acceleration,constant-velocity movement and deceleration) is reversed with respect tothe sequence where the head 120 is stopped.

In the conventional apparatus in which the component holder heads arecarried by the intermittently rotated rotary table, each head should bestopped at all of the stop positions. During a movement of the headcorresponding to the angular spacing pitch, therefore, the head isinitially accelerated from the zero velocity, and is then decelerated tothe zero velocity to be stopped at each stop position, as indicated by asolid line in the lower left block in FIG. 11B-1. To complete themovement of the head corresponding to the angular spacing pitch withinthe same time as in the present apparatus 12, the maximum velocity ofthe head in the conventional apparatus as indicated in FIG. 11B-2 shouldbe higher than that of the head 120 in the present apparatus 12 asindicated in FIG. 11A-2. Accordingly, the acceleration and decelerationvalues of the head in the conventional apparatus as indicated in FIG.11B-3 should be higher than those of the head 120 as indicated in FIG.11A-3. Thus, the required condition of movement of the head 120 in thepresent electronic component transferring and mounting apparatus 12 ismore moderate than that in the conventional apparatus. Accordingly, thepresent apparatus 12 is required to have a comparatively low degree ofstructural rigidity, and the required capacity of the main driveservomotor 1.08 for rotating the rotary plates 70 can be significantlyreduced, provided the component transferring efficiency of the presentapparatus 12 is the same as that of the conventional apparatus.Therefore, the cost of manufacture of the present apparatus 12 can bereduced, or the accuracy of positioning of the heads 120 at the stoppositions can be improved.

Conversely, the operating efficiency of the present apparatus 12 can beimproved by reducing the time of movements of the heads 120corresponding to the angular spacing pitch of the heads 120 or rotaryplates 70, namely, by reducing the time interval at which the successiverotary plates 70 sequentially reach a given stop position.

In the conventional apparatus in which the rotary table carrying theheads is intermittently rotated stopping at each stop position, eachhead should be accelerated from zero and decelerated to zero each timethe head is moved between the adjacent stop positions at which the headis held stopped for a given time, as described above. Suppose the timerequired for the movement corresponding to the angular spacing pitch is60 ms and the stop time is 20 ms, the time of the movement byacceleration and deceleration is 40 ms. Therefore, the average velocityof the head should be increased as compared with that in the presentapparatus 12.

In the present apparatus 12, the stop positions are provided at everythree or six angular spacing positions which are evenly spaced from eachother about the stationary shaft 66. Each head 120 is moved at aconstant velocity into a given angular spacing region between thenon-stop position and the stop position, and is decelerated to bestopped at the stop position. Therefore, a comparatively long time of 50ms is allowed for the actual movement. Accordingly, the overall timecorresponding to the angular spacing pitch can be reduced by a timewhich is substantially equal to a sum of a half (10 ms) of the stop time(20 ms) and a difference, a, between the time required for theaccelerating movement by an angle r and the time required for theconstant-velocity movement by the same angle, as indicated in FIG. 12.Consequently, the required time of movement of the head 120corresponding to the angular spacing pitch can be reduced by a timecorresponding to the above-indicated sum, and the component mountingefficiency can be accordingly increased. For instance, theconventionally required time of 90 ms corresponding to the angularspacing pitch can be reduced to as short as 60 ms in the presentelectronic component transferring and mounting apparatus 12.

The present apparatus 12 is further advantageous in that the twelvecomponent holder heads 120 are held by the respective rotary plates 70,and are rotated independently of each other, whereby the mass thatshould be accelerated and decelerated can be reduced, making it possibleto prevent an increase in the vibration and noise even if theacceleration and deceleration values of the mass (head 120) areincreased. This results in a further decrease in the required time ofmovement of the head 120 corresponding to the angular spacing pitch.

In the conventional apparatus in which the rotary table carrying aplurality of component holder heads is intermittently rotated, therotary table is generally provided with a plurality of cam followerrollers corresponding to the heads, and these rollers are sequentiallybrought into engagement with a roller gear cam, so that the rotary tableis intermittently rotated. This arrangement requires a comparativelyhigh degree of accuracy in the spacing pitch of the cam followerrollers, to prevent the rollers from exerting an excessive force on thesurface of the cam, which may reduce the life expectancy of the rollersand cause vibration and noise. In the present apparatus 12, on the otherhand, the individual rotary plates 70 has respective cam followerrollers 88 which engage the cam grooves 92 of the concave globoidal cams90 for rotating the rotary plates 70. In this arrangement, the twelvecam follower rollers 88 engage the concave globoidal cams 90,independently of each other and without influencing each other,excessive forces will not act on the rollers 88 engaging the cams 90,whereby the life expectancy of the rollers is improved while thevibration and noise are reduced.

Referring next to FIGS. 13-24, there is shown an electronic componentmounting system equipped with an electronic transferring and mountingapparatus according to another embodiment of this invention. In thepresent system, the electronic component transferring and mountingapparatus generally indicated at 380 in FIG. 13 uses two concavegloboidal cams and a constant-velocity rotor for rotating twelve rotarymembers such that each rotary member is stopped at a component suckingposition and a component mounting position, but is not stopped at animage taking position. The present apparatus is adapted such that twopositions are available for each of the component sucking and mountingpositions, and such that the height position of the component holderhead 120 upon a downward movement thereof at the component sucking andmounting positions and the height position of the electronic componentat the image taking position can be changed in two steps. In the otheraspects of the apparatus according to the present second embodiment, thepresent apparatus 380 is identical with the apparatus 12 of the firstembodiment. The same reference numerals as used in the first embodimentwill be used to identify the functionally corresponding elements, andredundant description of these elements of the present apparatus willnot be provided.

The electronic component transferring and mounting apparatus 380 has aframe 382 including a support plate 384 to which an engaging cam 386 isfixed, as shown in FIG. 13. A support shaft in the form of a main shaft388 is rotatably supported at its upper end portion by the engaging cam386. The main shaft 388 extends downwards through an opening 393 formedthrough a bottom wall 391 of a mounting structure 389 of the frame 382,such that the lower end of the main shaft 388 is located outside andbelow the frame 382. The main shaft 388 is rotatably supported at itslower end portion by a support plate 390 secured to the base 10. Thus,the main shaft 388 is supported rotatably about a vertically extendingaxis thereof. On this main shaft 388, there are rotatably supported aplurality of rotary members in the form of twelve rotary plates 392through respective twelve pairs of bearings 394. The rotary plates 392are rotatable about a common axis, which is the axis of the main shaft388.

The bearings 394 are identical with the bearings 72 in the firstembodiment, and are arranged in two arrays 396 which are spaced apartfrom each other in the axial direction of the main shaft 388. Each array396 consists of twelve bearings 394. The vacuum source is connectedthrough a conduit (not shown) to a passage (not shown) formed throughthe main shaft 388, and this passage is connected to the switchingdevice 178. Since the main shaft 388 is rotated, the above-indicatedconduit and the passage in the main shaft 388 are connected by a valve(not shown) which permits communication between the conduit and thepassage even while the main shaft 388 is rotated. The passage in themain shaft 388 is connected to the twelve switching devices 178 throughrespective hoses. A small angle of relative rotation of the switchingdevice 178 and the rotary plate 392 is permitted by elastic deformationof the hose.

The upper end portion of the main shaft 388 projects upwards from theengaging cam 386, and has a timing pulley 400 fixed thereto. The timingpulley 40 is connected through a timing belt 406 (FIG. 14) to a timingpulley 404 which is fixed to an output shaft of a drive source in theform of a main drive servomotor 402 (FIG. 21). The timing pulley 40 isrotated at a predetermined constant speed by the servomotor 402.

Two concave globoidal cams 410 a, 410 b are disposed at respectivepositions of the frame 382 corresponding to the component sucking andmounting positions. As shown in FIGS. 13 and 14, these concave globoidalcams 410 a, 410 b are disposed symmetrically with each other withrespect to the axis of the main shaft 388 such that axes of the cams 410lie in a horizontal plane and are parallel to each other. The cams 410a, 410 b are fixedly mounted on respective rotary shafts 412 a, 412 b,which are rotatably supported by respective pairs of brackets 413 a, 413b. As shown in FIG. 14, each rotary shaft 412 a, 412 b has a bevel gear414 a, 414 b fixed thereto at one end thereof. The bevel gears 414 a,414 b mesh with respective bevel gears 416 a, 416 b (FIG. 13) which arerotatable about vertical axes. These bevel gears 414 a, 414 b, 416 a,416 b have the same diameter.

As shown in FIG. 13, brackets 420 a, 420 b are fixed to the mountingstructure 389 of the frame 382, and rotary shafts 422 a, 422 b aresupported by the support plate 384 of the frame 382 and the brackets 420a, 420 b such that the rotary shafts 422 are rotatable about verticalaxes. The bevel gears 416 a, 416 b are fixedly mounted on the rotaryshafts 422 a, 422 b, respectively. The upper end portions of the rotaryshafts 422 a, 422 b project upwards from the support plate 384, and haverespective timing pulleys 424 a, 424 b fixed thereto. These timingpulleys 424 are held in rolling contact with the timing belt 406, whichis provided for transmitting a rotary motion of the main driveservomotor 402 to the main shaft 388 as described above. The timing belt406 is also engaged with an idler timing pulley 426. In the presentarrangement, the rotary shafts 422 a, 422 b are rotated by the maindrive servomotor 402, so that the bevel gears 416 a, 416 b, 414 a, 414 bare rotated to rotate the concave globoidal cams 410 a, 410 bsimultaneously in synchronization with each other.

The concave globoidal cams 410 a, 410 b have respective cam grooves 430a, 430 b, which are formed to rotate the rotary plates 392 at thevelocities described below. The cam grooves 430 a, 430 b are engageablewith cam follower rollers 436 fixed to the respective rotary plates 392.Immediately after these rollers 436 have entered the cam grooves 430 a,430 b, the rotary plates 392 are rotated at the same velocity as themain shaft 388. Then, the rotary plates 392 are accelerated for anincreased rotary movement distance per unit time, and are thendecelerated to be stopped at the component sucking or mounting position.During an operation to pick up or mount the electronic component at thesucking or mounting position, the appropriate rotary plate 392 is heldstopped. After the operation, the rotary plate 392 is accelerated, andis then decelerated so that the velocity of the rotary plate 392 uponmovement of the roller 436 away from the cam groove 430 a, 430 b is madeequal to the velocity of the main shaft 388 and so that the angularinterval of this rotary plate 392 with respect to the adjacent rotaryplate 392 located downstream in the rotating direction is 30°.

The cam groove 430 a of the concave globoidal cam 410 a is shown inFIGS. 15 and 16, by way of example. The cam groove 430 a has an inclinedportion 432 having a lead angle with respect to a plane perpendicular tothe axis of rotation of the concave globoidal cam 410 a, and a non-leadportion 434 which does not have such a lead angle and which isperpendicular to the axis of rotation. The inclined portion 432 has acomparatively small axial width as measured in the axial direction ofthe cam 410 a, so that the cam follower roller 436 engages this narrowinclined portion 432 with a small amount of clearance to the sidesurfaces of the narrow inclined portion 432 in the diametric directionof the roller 436. The non-lead portion 434 has a larger axial widththan the inclined narrow portion 432, so that this wide non-lead portion434 permits the roller 436 to move in the axial direction. The camgroove 430a also has an intermediate width varying portion 438 betweenthe narrow inclined portion 432 and the wide non-lead portion 434. Theaxial width of the width varying portion 438 gradually increases in thedirection from the narrow inclined portion 432 toward the wide non-leadportion 434.

When the cam follower cam 436 is in engagement with the wide non-leadportion 434, the rotary plate 392 is held stopped. Since the axial widthof the non-lead portion 434 is larger than the diameter of the roller436, two positions, namely, first and second positions, are available asthe actual stop position of the rotary plate 392. In the first position,the roller 436 is in contact with an upstream side surface 440 of thenon-lead portion 434, as indicated in solid line in FIG. 15. In thesecond position, the roller 436 is in contact with a downstream sidesurface 442 of the non-lead portion 434. The side surfaces 440, 442 arelocated on the upstream and downstream sides, respectively, as viewed inthe rotating direction of the rotary plate 392. One of the first andsecond positions is selected as the actual stop position (componentsucking or mounting position). The concave globoidal cams 410 a, 410 bare disposed at the positions of the frame 382 corresponding to thecomponent sucking and mounting positions, which are spaced apart fromeach other by 180°. The axial dimension of the non-lead portion 434 isdetermined so that the distance between the first and second positionsin the X-axis direction is equal to 8 mm. The first and second positionsselectively established as the component sucking position will bereferred to as first and second sucking positions, while the first andsecond positions selectively established as the component mountingposition will be referred to as first and second mounting positions.

The cam grooves 430 a, 430 b of the concave globoidal cams 410 a, 410 bare formed such that the rotary plate 392 is rotated at the samevelocity as the main shaft 388 after the cam follower roller 436 isdisengaged from the cams 410 a, 410 b, and the angular interval of thisrotary plate 392 with respect to the next downstream rotary plate 392 is30° when the roller 436 is disengaged from the cams 410, irrespective ofwhether the rotary plate 392 is stopped at the first or second componentsucking or mounting position.

In the present electronic component transferring and mounting apparatus380, the two head elevating and lowering devices 260 described abovewith respect to the first embodiment are disposed at the positions ofthe frame 382 corresponding to the component sucking and mountingpositions. In FIGS. 13 and 14, only the device 260 corresponding to thecomponent mounting position is shown. In the present apparatus 380,however, a hypoid gear (not show) is fixedly and concentrically mountedon the support shaft 322 of the head elevating and lowering cam 318 ofthe head elevating and lowering device 260. This hypoid gear meshes witha hypoid gear 446 (FIG. 13) rotatably attached to the frame 382. Thesehypoid gears have the same diameter. The hypoid gear 446 is fixedlymounted on a rotary shaft 450 which is supported by the support plate384 of the frame 382 and a bracket 448 fixed to the mounting structure389 of the frame 382. The rotary shaft 450, which is rotatable about avertical axis thereof, has a timing pulley 452 fixed to its upper endportion projecting upwards from the support plate 384. The timing pulley452 is held in rolling contact with the above-indicated timing belt 406,so that a rotary motion of the main drive servomotor 402 is transmittedto the head elevating and lowering cam 318 through the hypoid gear 446,whereby the cam 318 is rotated.

Thus, the drive source in the form of the main drive servomotor 402 iscommonly used for the main shaft 388, two concave globoidal cams 410 a,410 b and head elevating and lowering cam 318. The diameter of thetiming pulley 452 for rotating the cam 318 is determined so that thetiming pulley 452 and the cam 318 are rotated through 360° duringrotation of the main shaft 388 through 30°. The diameter of the timingpulleys 410 a, 410 b is determined so that these pulleys 410 are rotatedthrough 180° during rotation of the main shaft 388 through 30°. Thus,the cam 318 is rotated one full turn within a time corresponding to theangular spacing pitch of the rotary plates 392, namely, each time therotary plates 392 sequentially reach the component mounting position.

As shown in FIGS. 13 and 14, a constant-velocity rotary disc 460 isfixedly and concentrically mounted on a portion of the main shaft 388between the engaging cam 386 and the upper array 396 of the bearings 394to which the rotary plates 392 are fixed. The main shaft 388 and theconstant-velocity rotary disc 460 cooperate to constitute aconstant-velocity rotor. The constant-velocity rotary disc 460 isrotated at a predetermined constant velocity together with the mainshaft 388. The rotary disc 460 carries engaging members in the form oftwelve engaging pins 468 fixed thereto. These pins 468, which constitutean engaging device 464, are equi-angularly spaced from each other aboutthe axis of the rotary disc 460.

The constant-velocity rotary discs 460 further carries guide members inthe form of twelve guide pins 466. These guide pins 466 engage therotary disc 460 such that the pins 466 are movable relative to therotary disc 460 in the axial direction of the rotary disc 460. Theengaging pins 468 are located radially outwardly of the guide pins 466,and engage the constant-velocity rotary disc 460 such that the pins 468are movable relative to the rotary disc 460 in the axial direction ofthe disc 460. The lower portion of each engaging pin 468 projectsdownwards from the rotary disc 460, and has a tapered lower end 470whose diameter decreases in the downward direction. The guide pin 466and the corresponding engaging pin 468 are connected to each other attheir upper ends by a connecting plate 474, so that the guide pins 466guides the corresponding engaging pin 468 in the axial direction, andprevents rotation of the engaging pins 468.

To the upper surface of the connecting plate 474, there is attached acam follower roller 478 such that the roller 478 is rotatable about anaxis which extends in a radial direction of the main shaft 388. Theroller 478 is held in engagement with a cam groove 480 formed in theengaging cam 386 described above. The cam 386 has a cylindrical outercircumferential surface coaxial with the main shaft 388, and the camgroove 480 is formed and open in the outer circumferential surface ofthe cam 386. The cam groove 480 has a height-varying portion and anon-lead portion. The height-varying portion is a portion whose heightposition in the axial direction of the main shaft 388 gradually varies,and the non-lead portion is a portion whose height position isunchanged. When the constant-velocity rotary disc 460 is rotated withthe main shaft 388, the cam follower roller 478 is rotated with therotary disc 460 about the axis of the main shaft 388, and at the sametime is elevated and lowered or held at a predetermined level. As aresult, the engaging pins 468 are similarly rotated and verticallymoved.

The twelve rotary plates 392 have respective engaging recesses 486 openin their upper end faces. Each of these engaging recesses 486 has atapered surface whose taper angle corresponds to the taper angle of thetapered end of the corresponding engaging pin 468. The engaging pins 468are engaged with and disengaged from the respective recesses 486 whenthe pins 468 are moved up and down. With the engaging pin 468 engagingthe recess 486 of a given rotary plate 392, this rotary plate 392 isrotated at a predetermined velocity by the constant-velocity rotary disc460.

The cam groove 480 of the cam 386 is shaped so that the following eventswill take place for a given rotary plate 392 when the main shaft 388 isrotated.

The engaging pin 468 corresponding to the rotary plate 392 in questionis disengaged or released from the engaging recess 486 (namely, the pin468 is moved upwards), after the cam follower roller 436 has been movedinto the cam groove 430 a, 430 b and while the rotary plate 392 isrotated by the concave globoidal cam 410 a, 410 b at the same constantvelocity as the constant-velocity rotary disc 460. Then, the engagingpin 468 is held released from the recess 486 until the pin 468 is againbrought into engagement with the recess 468, so that the pin 468 doesnot disturb a rotary motion of the rotary plate 392 by the concavegloboidal cam 410 a, 410 b. The engaging pin 468 is engaged with therecess 486 (namely, the pin 468 is moved downwards), before the roller436 has been moved out of the cam groove 430 a, 430 b and while therotary plate 392 is rotated at the same velocity as theconstant-velocity rotary disc 460. The pin 468 is held engaged with therecess 486 to cause the rotary plate 392 to be rotated by theconstant-velocity rotary plate 460 until the roller 346 is again broughtinto engagement with the cam groove 430 a, 430 b to cause the rotaryplate 392 to be rotated by the concave globoidal cam 410 a, 410 b. Sincethe engaging pin 468 has the tapered end 470, the pin 468 can besmoothly brought into engagement with the engaging recess 486.

The rotary plate 392 is rotated by the concave globoidal cams 410 a, 410b, in the vicinities of the component sucking and mounting positions,and is rotated at the predetermined constant velocity by theconstant-velocity rotary disc 460, between the component sucking andmounting positions. The rotary plate 392 can be stopped by the concavegloboidal cams 410 a, 410 b, at the component sucking and mountingpositions with high positioning accuracy. The image taking position atwhich the image of the electronic component is taken is located betweenthe component sucking and mounting positions, and a high-speed camera562 with a stroboscope (FIG. 21) is provided at a position of the base10 corresponding to the vicinity of the image taking position. Therotary plate 392 is rotated at the constant velocity by theconstant-velocity rotary disc 460, between the component sucking andmounting positions, without stopping at the image taking position. Theimage of the electronic component 164 is taken by the high-speed camera562 when the component 164 passes a position right above the camera 562.

Between the twelve rotary plates 392 and the constant-velocity rotarydisc 460, there are provided twelve stop position changing air cylinders490 for changing the stop position of the rotary plate 392, as shown inFIGS. 13 and 18. Each air cylinder 490 has a cylinder housing 492 whichis connected by a pin to a bracket 494 fixed to the constant-velocityrotary disc 460, such that the cylinder housing 492 is rotatable aboutan axis which extends in the axial direction of the rotary disc 460. Theair cylinder 490 further has a piston rod 498 which is connected by apin to the rotary plate 392 such that the piston rod 498 is rotatableabout an axis which also extends in the axial direction of the rotarydisc 460.

The twelve stop position changing air cylinders 490 are connected to theconstant-velocity rotary disc 460 such that the connections of theadjacent two air cylinders 490 to the rotary disc 460 are located atdifferent radial positions (i.e., at relatively outer and innerpositions) of the rotary disc 460, in order to prevent an interferenceof the adjacent air cylinders 490. To this end, the every two rotaryplates 392 have respective radial extensions 500 radially outwardlyextending from the upper ends thereof, as shown in FIGS. 13 and 18. Theradial extensions 500 have respective cutouts 501 formed in their uppersurfaces, as shown in FIGS. 13 and 18, to avoid interferences of thoseradial extensions 500 with the air cylinders 490 connected to the rotaryplates 392 not provided with the radial extensions 500. The bracket 494for supporting the air cylinder 490 connected to the rotary plate 392not provided with the radial extension 500 is located above orhorizontally spaced apart from the cylinder housing 492 of the aircylinder 490 connected to the adjacent rotary plate 392, so that thebracket 494 does not interfere with that cylinder housing 492.

Each stop position changing air cylinder 490 is a double-acting cylinderhaving two air chambers. By controlling flows of compressed air into andfrom these two air chambers, the corresponding rotary plate 392 ispivoted by the air cylinder 490 about the axis of the main shaft 388, sothat the cam follower roller 436 is selectively moved to the first andsecond sucking or mounting positions in which the roller 436 is forcedagainst the upstream and downstream side surfaces 440, 442 of the camgroove 430 a, 430 b, respectively, as indicated by solid and two-dotchain lines in FIG. 15.

In the present electronic component transferring and mounting apparatus380, too, a stationary cylindrical cam 504 is fixed to the underside ofthe frame 382, and cam follower rollers 502 are held in rollingengagement with a cam groove 506 formed in the cylindrical cam 504. Likethe rollers 126 provided in the apparatus 12 according to the firstembodiment, each of the rollers 502 is fixed to the vertical slide 124which is vertically movably supported by the rotary plate 392. Asdescribed above with respect to the apparatus 12, the component holderhead 120 is attached to the vertical slide 124. In the present apparatus380, the circumferential dimension (as measured in the rotatingdirection of the rotary plate 392) of the vertically movable member 266of the head elevating and lower device 260 disposed at the positioncorresponding to the component sucking position is determined so thatthe cam follower roller 502 is located in the groove 272 when the rotaryplate 392 is stopped at the first or second sucking position, namely,irrespective of whether the rotary plate 392 is located at the first orsecond sucking position. The circumferential dimension of the verticallymovable member 266 of the head elevating and lowering device 260disposed at the position corresponding to the component mountingposition is similarly determined.

As schematically illustrated in FIG. 17, the cam groove 506 has a firstwide portion 508, a second wide portion 509 and a third wide portion511, which have respective constant heights or whose levels do not varyin the circumferential direction of the cylindrical cam 504. The firstwide portion 508 corresponds to the component sucking position and itsvicinity. The second wide portion 509 corresponds to the componentmounting position and its vicinity. The third wide portion 511corresponds to the image taking position and its vicinity. The width orvertical dimension of the first wide portion 508 as measured in theaxial direction of the main shaft 388 is equal to a diameter of the camfollower roller 502 plus 6 mm, so that the roller 502 is permitted to bemoved in the first wide portion 508 in the vertical direction. The widthor vertical dimension of the second wide portion 509 is equal to thediameter of the roller 502 plus 4 mm, while the width or verticaldimension of the third wide portion 511 is equal to the diameter of theroller 502 plus 3 mm. These second and third wide portions 509, 511 alsopermit the roller 502 to move therein in the vertical direction. The camgroove 506 further has a first narrow portion 510 which has a constantheight and which is located upstream of the component sucking positionas viewed in the rotating direction of the rotary plates 392. The widthor vertical dimension of this first narrow portion 510 is determinedsuch that the roller 502 is in rolling engagement with the first narrowportion 510 with substantially no clearance therebetween in the verticaldirection. The cam groove 506 also has a second narrow portion 514 whoseheight or level varies in the circumferential direction. The cam groove506 has width varying portions 512 which connect the portions havingdifferent widths. The width of these varying portions 512 graduallyvaries to smoothly connect the adjacent portions of the groove 506.

The width or vertical dimension of the first wide portion 508 is equalto the vertical dimension (as measured in the axial direction of themain shaft 388) of the groove 272 formed in the vertically movablemember 266 of the head elevating and lowering device 260 disposed at theposition corresponding to the component sucking position. The width orvertical dimension of the second wide portion 509 is equal to thevertical dimension of the groove 262 of the vertically movable member266 of the head elevating and lowering device 260 disposed at theposition corresponding to the component mounting position. Asignificance of the difference between the vertical dimensions of thefirst and second wide portions 508, 509 will be described.

As shown in FIG. 13, each of the twelve rotary plates 392 is providedwith a height position changing air cylinder 520 attached thereto so asto extend in the vertical direction. The air cylinder 520 has a pistonrod 522 which has an engaging member 524 fixed thereto. The engagingmember 524 is fixed to the vertical slide 124 which carries thecomponent holder head 120. The height position changing air cylinder 520is a double-acting cylinder whose piston rod 522 is adapted tovertically move the vertical slide 124 and the cam follower roller 502fixed thereto, so that the roller 502 can be selectively brought intopressing contact with an upper side surface 526 and a lower side surface528 (FIG. 17). When the vertical slide 124 is vertically moved by thestationary cylindrical cam 504 and the cam follower roller 502, thedirection of movement of the vertical slide 124 may be reversed withrespect to the direction in which the cam follower roller 502 is biasedby the height position changing air cylinder 520. In this case, thevertical movement of the vertical slide 124 may be permitted bycompression of the air in one of the two air chambers of the aircylinder 520 which is connected to the air source. However, it isdesirable that the vertical movement of the vertical slide 124 ispermitted by permitting a discharge flow of the air from the air chamberconnected to the air source. This latter arrangement prevents avariation in the air pressure in that air chamber, making it possible toforce the roller 502 onto the side surface of the cam groove 506 with aconstant force.

When the cam follower roller 502 is in pressing contact with the upperside surface 526, the component holder head 120 has a larger height atthe first or second sucking position or first or second mountingposition, than when the roller 502 is in pressing contact with the lowerside surface 528. Thus, the height position changing air cylinder 520permits the height position of the head 120 (in the axial direction ofthe main shaft 388) to be changed in two steps when the head 120 isstopped at the component sucking and mounting positions. Further, theair cylinder 520 permits the height position of the head 120 to bechanged in two steps when the head 120 passes the image taking position.Thus, there are available two height positions of the head 120 at eachof the first and second sucking positions (in the component suckingstation), first and second mounting positions (in the component mountingstation), and image taking position (in the image taking station).

Flows of compressed air into and from the stop position changing aircylinders 490 and the height position changing air cylinders 520 arecontrolled by twelve stop position changing valves 530 and twelve heightposition changing valves 532, as shown in FIGS. 13 and 19. These valves530, 532 are attached to the constant-velocity rotary disc 460 such thatthe twelve pairs of these valves 530, 532 corresponding to the twelverotary plates 392 are equi-angularly spaced from each other in thecircumferential direction of the rotary disc 460. Each of these valves530, 532 includes a switching member in the form of a spool which ismoved between two operating positions for mechanically controlling thesupply and discharge flows of the compressed air into the appropriatecylinder 490, 520. The stop position changing valve 530 and the heightposition changing valve 530 of each pair are spaced apart from eachother in the radial direction of the rotary disc 460, as shown in FIG.19. The stop position changing valves 530 are controlled by first andsecond valve switching devices 534, 536, while the height positionchanging valves 532 are controlled by a third valve switching valve 538,as shown in FIGS. 18-20.

Referring to FIG. 18, there are shown twelve angular positions which areequi-angularly spaced from each other at an angular interval of 30° inthe clockwise direction about the main shaft 388. Suppose the stop andheight changing valves 530, 532 corresponding to the rotary plate 392located at the component sucking position are located at the firstangular position, the valves 530, 532 corresponding to the rotary plate392 located at the component mounting position are located at theseventh angular position, and the valves 530, 532 corresponding to therotary plate 392 at the image taking position for taking an image of thecorresponding electronic component are located at the fourth angularposition.

As shown in FIG. 18, the first and second valve switching devices 534,536 for the stop position changing valves 530 are located at the fifthand eleventh angular positions, respectively, while the third valveswitching device 538 for the height position changing valves 532 islocated at the tenth angular position.

The three valve switching devices 534, 536, 538 have the sameconstruction. The first valve switching device 534 for the stop positionchanging valves 530 will be described by way of example, by reference toFIG. 19. The first valve switching device 534 has two actuating membersin the form of engaging rollers 540, 542 disposed such that theserollers 540, 542 are located above and below the spool of each stopposition changing valve 530 when the valve 530 is located at the fifthangular position (FIG. 18). The first valve switching device 534 furtherhas a drive device in the form of two valve switching air cylinders 544,546 fixed to the frame 382. The air cylinders 544, 546 have respectivepiston rods 548, 550. The rollers 540, 542 are fixed to the free ends ofthe piston rods 548, 550 such that the rollers 540, 542 are rotatableabout horizontal axes extending in the radial direction of the mainshaft 388. The air cylinders 544, 546 are single-acting cylinders whosepistons rods 548, 550 are spring-biased so that the rollers 540, 542 arenormally held in their positions in which the rollers 540, 542 arespaced apart from the end faces of the spool of the stop positionchanging valve 530. Like the first valve switching device 534, thesecond valve switching device 536 located at the eleventh angularposition is disposed at a position aligned with the stop positionchanging valves 530 in the radial direction of the main shaft 388, andthe third valve switching device 538 located at the tenth angularposition is disposed at a position aligned with the height positionchanging valves 532 in the radial direction of the main shaft 388.

The compressed air is supplied from the air source through a conduit(not shown) to a passage formed through the main shaft 388. This passageis connected to the stop position changing valves 530 and the heightposition changing valves 532 through the constant-velocity rotary disc460. Each stop position changing valve 530 is connected to the stopposition changing air cylinder 490 through a hose (not shown), whileeach height position changing valve 532 is connected to the heightposition changing air cylinder 520 through a hose (not shown). Since themain shaft 388 is rotated, the above-indicated conduit and passage inthe main shaft 388 are connected to each other by a rotary joint.

The present electronic component mounting system including theelectronic component transferring and mounting apparatus 380 iscontrolled by a control device 560 illustrated in the block diagram ofFIG. 21. This control device 560 is principally constituted by thecomputer 340 as used in the control device 330 in the first embodiment.The high-speed camera 562 is connected to the input interface 342 of thecomputer 340. To the output interface 344 of the computer 340, there areconnected the driver circuit 352 for the main drive servomotor 402, anddriver circuits 564 for controlling the valve switching air cylinders544, 546 of each of the first, second and third valve switching devices534, 536, 538. The ROM 334 of the computer 340 stores various controlprograms including programs for controlling operations for the componentholder heads 120 to hold the electronic components and mount them on theprinted-circuit board 38, programs for selecting the first or secondsucking position and the first or second mounting position, and programsfor selecting the height positions of the heads 120 at the componentsucking and mounting position and image taking position.

When the present electronic component mounting system is operated tomount the electronic components on the printed-circuit board 38, themain drive servomotor 402 is activated to rotate the constant-velocityrotary disc 460 and the concave globoidal cams 410 a, 410 b, so that thetwelve rotary plates 392 are rotated independently of each other,namely, accelerated, decelerated, moved at a predetermined constantvelocity or stopped, depending upon their positions in their circularpath. Each rotary plate 392 is rotated by the constant-velocity rotarydisc 460 at the constant velocity while the engaging pin 468 of thecorresponding engaging device 464 is held in engagement with theengaging recess 486 of the rotary plate 392 in question. The rotaryplate 392 is rotated by the concave globoidal cams 410 a, 410 b whilethe corresponding cam follower roller 436 is held in engagement with thecam grooves 434 a, 434 b of the cams 410 a, 410 b and while the roller436 is located at positions other than the component sucking andmounting positions. The rotary plate 392 is stopped at the componentsucking and mounting positions so that the electronic component 164 ispicked up by the corresponding component holder head 120 and mounted onthe printed-circuit board 38.

When the rotary plate 392 is passing the image taking station, therotary plate 392 is rotated by the constant-velocity rotary disc 460 atthe constant velocity with the pin 468 in engagement with the recess486. The image of the electronic component 164 held by the head 120 istaken by the high-speed camera 562 when the rotary plate 392 passes theimage taking position during its rotary movement at the constantvelocity. Since the high-speed camera 562 is provided with astroboscope, the image of the electronic component 164 can be taken witha sufficiently high quality without having to stop the electroniccomponent 164. The X-axis and Y-axis and angular position errors of theelectronic component 164 are calculated on the basis of the output ofthe high-speed camera 562, and the angular position of the electroniccomponent 164 is adjusted to remove the angular positioning error byrotating the suction nozzle 158 about its axis while the head 120 ismoved from the image taking position to the component mounting position.

As described above, there are two stop positions at which the rotaryplate 70 is stopped. Around each of the component sucking position andthe component mounting position, the rotary plate 70 is rotated withacceleration, at a constant velocity, and with deceleration. At theremaining portion of the circular movement path, the rotary plate 70 isrotated at a constant velocity. The timing chart of FIG. 36 shows arelationship between the time and the angle of rotation of each of thetwelve rotary plates 70, in the same manner as that employed in thetiming chart of FIG. 10. Although in the present embodiment there areprovided two selectable component sucking positions and two selectablecomponent mounting positions, the timing chart of FIG. 36 is, for easierunderstanding purposes only, based on the assumption that the respectivenon-lead portions 434 of the cam grooves 430 a, 430 b of the concavegloboidal cams 410 a, 410 b have a width which does not permit theroller 436 to be moved in the direction of the width and accordinglythere is provided a single component sucking position and a componentmounting position. This assumption applies to FIGS. 11A-1 to 11A-3 and11B-1 to 11B-3 which will be referred to, as needed, in the followingdescription. It will be understood from the timing chart of FIG. 36 thatthe individual rotary plates 70 are rotated independently of each otherso that the ten rotary plates 70 can be rotated about the stationaryshaft 66 while the two rotary plates 70 are held stopped at thecomponent sucking and component mounting positions, for thecorresponding heads 120 to pick up and mount the components 164. Thepresent electronic component transferring and mounting apparatus 380having the twelve component holder heads 120 has only two stoppositions, so that the required acceleration and deceleration values ofthe heads 120 can be reduced, as compared with those in the conventionalcomponent transferring device in which a plurality of component holderheads are carried by an intermittently rotated rotary table. Suppose theconventional rotary table carries twelve heads arranged along a circlewhose diameter is the same as that of the circle along which the heads120 are rotated, and suppose the time required for one full rotation ofthe conventional rotary table is the same as the time T in the presentapparatus 380, the required acceleration and deceleration values of theheads 120 in the present apparatus 380 are smaller than those in theconventional apparatus using the conventional rotary table, for thereason described above with respect to the timing chart of FIG. 10.

Meanwhile, in the present embodiment, there are provided two selectablecomponent sucking positions and two selectable component mountingpositions. When the rotary plate 70 is stopped at the upstream one ofthe two selectable component sucking or mounting positions in therotating direction thereof, the component holder head 120 is rotated ata slope smaller than that of a curve indicated at solid line in FIG.11A-1, that is, rotated along a curve slightly below the solid-linecurve, before the head 120 is stopped at a position slightly below thestop position indicated by the solid-line curve (i.e., position withzero or no dimensionless displacement). Thus, the component holder head120 can be moved more slowly to the upstreamside stop position. Afterthe rotation of the rotary plate 70 is resumed, the holder head 120 isrotated at a slope greater than that of the solid-line curve shown inFIG. 11A-1, that is, rotated along a curve slightly above the solid-linecurve, so as to compensate for the distance between the upstream-sideand downstream-side stop positions in the rotating direction. Thus, theholder head 120 is placed in the state in which the head 120 is rotatedat a constant velocity, at the same timing as that at which the holderhead 120 is rotated in the first embodiment wherein the globoidal cams90 each having no no-lead portion 434 are employed. Therefore, thecomponent holder head 120 is moved at velocities slightly smaller thanthose of a curve indicated at solid line in FIG. 11A-2, and ataccelerations or decelerations slightly smaller than those of a curveindicated at solid line in FIG. 11A-3, before the head 120 is stopped.On the other hand, after the rotation of the rotary plate 70 is resumed,the holder head 120 is rotated at velocities slightly greater than thoseof the solid-line curve shown in FIG. 11A-2, and at accelerations ordecelerations slightly greater than those of the solid-line curve shownin FIG. 11A-3.

When the rotary plate 70 is stopped at the downstream one of the twoselectable component sucking or mounting positions in the rotatingdirection thereof, the component holder head 120 is rotated, conversely,at a slope greater than that of the solid-line curve shown in FIG.11A-1, that is, rotated along a curve slightly below the solid-linecurve, before the head 120 is stopped at a position slightly above thestop position indicated by the solid-line curve (i.e., position withzero or no dimensionless displacement). In order to move additionallyover the distance between the upstream-side and downstream-side stoppositions in the rotating direction, the component holder head 120 isrotated more quickly to the downstream-side stop position. After therotation of the rotary plate 70 is resumed, the holder head 120 isrotated at a slope smaller than that of the solid-line curve shown inFIG. 11A-1, that is, rotated along a curve slightly below the solid-linecurve, because the head 120 was stopped at the downstream-side stopposition. The holder head 120 is placed in a constant-velocity state, atthe same timing as that at which the holder head 120 is rotated in thefirst embodiment. Therefore, the component holder head 120 is moved atvelocities slightly greater than those of the solid-line curve shown inFIG. 11A-2, and at accelerations or decelerations slightly greater thanthose of the solid-state curve shown in FIG. 11A-3, before the head 120is stopped. On the other hand, after the rotation of the rotary plate 70is resumed, the holder head 120 is rotated at velocities slightlysmaller than those of the solid-line curve shown in FIG. 11A-2, and ataccelerations or decelerations slightly smaller than those of thesolid-line curve shown in FIG. 11A-3.

In the present embodiment wherein there are provided two selectablecomponent sucking positions and two selectable component mountingpositions for the component holder heads 120, each of the heads 120 isrotated at different accelerations and decelerations from those in thecase where there are provided a single component sucking position and asingle component mounting position. However, those differences aresmall. On the other hand, like the first apparatus 12, the presentapparatus 380 enjoys the advantage that the component holder heads 120are moved at smaller accelerations and decelerations than those at whichthe holder heads of the conventional apparatus are moved. Thus, eachholder head 120 can reach each of the two stop positions in a shortertime. In addition, since each rotary plate 70 is rotated by the concavegloboidal cams 410 a, 410 b around the component sucking and mountingpositions, respectively, it can be stopped with accuracy at each of thesucking and mounting positions.

As the two rotary plates 392 which are 180° spaced from each other aboutthe axis of the main shaft 388 are rotated toward the component suckingand mounting positions, the corresponding cam follower rollers 502 aremoved from the cam groove 506 of the stationary cylindrical cam 504 intothe grooves 272 of the vertically movable members 266 of the two headelevating and lowering devices 260 disposed at the positionscorresponding to the sucking and mounting positions. With the devices260 operated to elevate the vertically movable members 266, thecorresponding two component holder heads 120 are vertically moved sothat the electronic component 164 is picked up by one of these two heads120 while the electronic component 164 held by the other head 120 istransferred to the printed-circuit board 38, as described above withrespect to the first embodiment. In portions of these component pickupand mounting operations, the rotation and vertical movement of the heads120 are contemporaneously effected, as also described above. In thepresent electronic component transferring and mounting apparatus 380,however, one of the first and second sucking positions is selected asthe component sucking position, and one of the first and second mountingpositions is selected as the component mounting position, so that theheight positions of the heads 120 at the component sucking and mountingpositions and the image taking position are changed according to theselected sucking and mounting positions.

An operation to pick up the electronic component 164 will be firstdescribed. Before the apparatus 380 is started, the multiplicity ofcartridges 22 are arranged on the cartridge support block 20, in theorder in which the electronic components are mounted on theprinted-circuit board 38.

Usually, the successive component holder heads 120 successively receivea plurality of electronic components from one of the cartridges 22, andthe following successive component holder heads 120 receive a pluralityof electronic components from the next cartridges 22. Thus, thesuccessive heads 120 receive the electronic components from thesuccessive cartridges 22 as the cartridge support block 20 isintermittently fed to sequentially bring the successive cartridges 22 atthe predetermined component supply position at which the predeterminednumber of electronic components is supplied from this cartridge 22 tothe corresponding number of successive heads 120. When the predeterminednumber of electronic components have been supplied from one cartridge22, the cartridge support block 20 is fed by a predetermined distance.At this time, the component sucking position is changed from one of thefirst and second sucking positions to the other position, for the reasonexplained below.

For example, the cartridges 22 are arranged on the cartridge supportblock 20 at a spacing pitch of 16 mm, and the cartridge support block 20is intermittently fed at a feed pitch of 8 mm, as indicated in FIG. 22A.When the cartridge 22 placed in the predetermined component supplyposition is changed from one cartridge to another, the cartridge supportblock 20 must be fed by a distance equal to the feed pitch multiplied bytwo.

If the operation to pick up the electronic component at the componentsucking position is initiated only after the new cartridge 22 has beenmoved to the component supply position by two intermittent feedingmovements of the cartridge support block 20 by a distance of 16 mm equalto the spacing pitch of the cartridges 22, the required operation timecorresponding to the angular spacing pitch of the heads 12 is inevitablyincreased with a result of lowering of the component mounting efficiencyof the apparatus 380.

If the electronic components are supplied from the cartridges 22 whilethe cartridge support block 20 is intermittently fed in a forwarddirection indicated by arrow P in FIG. 22 (which is opposite to thedirection of rotation of the rotary plates 392 indicated by arrow Q),the rotary plates 392 are normally stopped at the first sucking positionof FIG. 22A. In this first sucking position, the cam follower roller 436is in pressing contact with the upstream side surface 44 of the non-leadportion 434 of the cam groove 430 a of the concave globoidal cam 410 a.The position in the electronic component supply device 14 right belowthe head 120 stopped at the first sucking position will be referred toas “first component supply position”.

After the last one of the predetermined number of electronic componentsis picked up from the cartridge 22C by the head 120A, as indicated inFIG. 22A, the cartridge support block 20 is fed in the forward directionP by a distance of 8 mm, and the rotary plate 392 carrying the next head120B for picking up the first one of the predetermined number ofelectronic components from the next cartridge 22B is stopped at thesecond sucking position as indicated in FIG. 22B. As described above,the first and second sucking positions are spaced apart from each otherby a distance of 8 mm in the X-axis direction, that is, in the feedingdirection of the cartridge support block 20. Consequently, the cartridge22B and the rotary plate 392B are moved relative to each other by adistance of 16 mm. Therefore, the head 120B does not have to wait forthe completion of the 16 mm movement of the cartridge 22B before thehead 120B starts picking up the first one of the predetermined number ofelectronic components from the cartridge 22B. The position of theelectronic component supply device 14 right below the head 120 stoppedat the second sucking position will be referred to as “second componentsupply position”.

When the rotary plate 392 is stopped at the second sucking position, thecam follower roller 436 is moved by the stop position changing aircylinder 490 to be forced against the downstream side surface 442 of thecam groove 430 a, as indicated by two-dot chain line in FIG. 15. To thisend, the stop position changing valve 530 corresponding to the rotaryplate 392 to be stopped at the second sucking position is switched bythe second valve switching device 536 to stop the rotary plate 392 atthe second sucking position, when the above-indicated stop positionchanging valve 530 has reached the eleventh angular position shown inFIG. 18. However, this switching operation of the valve 530 by theswitching device 536 is effected only where the valve 530 has been heldin the position corresponding to the first sucking position before thecorresponding rotary plate 392 has reached the eleventh angularposition.

The concave globoidal cams 410 a, 410 b and the main shaft 388 aredriven by the main drive servomotor 402 such that the angles of rotationof the cams 410 and main shaft 388 are proportional to the angle ofrotation of the servomotor 402. Accordingly, the positions of the twelverotary plates 392 about the main shaft 388 can be determined on thebasis of the amount of rotation of the servomotor 402. Therefore, therotary plate 392 which has reached the eleventh angular position can beidentified. Further, the electronic component that is to be picked up bythe head 120 carried by that rotary plate 392, and the first or secondsucking position that should be selected for that rotary plate 392 canbe determined from the component sucking and mounting control programs.Accordingly, the stop position changing valves 530 of the rotary plates392 can be suitably controlled when the rotary plates 392 have reachedthe eleventh angular position, so that the rotary plates 392 can besuitably stopped at the first or second sucking position depending uponthe electronic component to be picked up from one of the cartridges 22.

The air chamber of each valve switching single-acting air cylinder 544,546 is kept open to the atmosphere except when the stop positionchanging valve 530 is switched. Therefore, the piston rods 548, 550 ofthese air cylinders 544, 546 are normally kept by the biasing springs inthe positions to hold the rollers 540, 542 in their non-operatingpositions in which the spool of the valve 30 is not operated even whenthe valve 30 has reached the eleventh angular position. When the valve530 is switched, one of the two valve switching air cylinders 544, 546is actuated to move the corresponding one of the rollers 540, 542 to theoperating position, whereby the spool of the valve 530 is moved foractuating the air cylinder 490. The spool of the stop position changingvalve 530 moved with the constant-velocity rotary disc 460 is broughtinto contact with one of the two rollers 540, 542 which is now placed inthe operating position, so that the spool is pushed by contact with thecircumferential surface of that roller 540, 542. Thus, the valve 530 isswitched to actuate the air cylinder 490 for biasing the rotary plate392 so as to cause the cam follower roller 436 to be forced against theupstream side surface 440 or downstream side surface 442 of the camgroove 430 a of the concave globoidal cam 410 a, whereby the rotaryplate 392 is stopped at the first or second sucking position. The roller540, 542 which has been moved to the operating position is returned tothe non-operating position if the component sucking position is notchanged for the next rotary plate 392 which reaches the eleventh angularposition. If the component sucking position is changed for the nextrotary plate 392, the roller 540, 542 is held in the operating position.

The valve switching air cylinders 544, 546 of the second valve switchingdevice 536 at the eleventh angular position are provided to switch thestop position changing valves 530 while the rotary plates 392 arerotated about the main shaft 388. Since the air cylinders 544, 546 areprovided with the rollers 540, 542 for contact with the spools of thevalves 530, the valves 530 can be smoothly switched without disturbingthe rotary movement of the rotary plates 392. The same advantage isoffered by the valve switching air cylinders 544, 546 of the first valveswitching device 534 (for switching the stop position changing valves530 at the fifth angular position) and the third valve switching device538 (for switching the height position changing valves 532 at the tenthangular position). Since the rollers 540, 542 are normally held in theirnon-operating positions, these rollers do not move into the path of thespools and operate the valves 530, except when valves 530 should beswitched. In other words, neither the roller 540 nor the roller 542 lieson a movement path of the spools of the valves 530 when the air chambersof the air cylinders 544, 546 are held open to the atmosphere.

The switching of the stop position changing valve 530 is initiated atthe eleventh angular position, which is spaced from the componentsucking position in the direction opposite to the rotating direction ofthe rotary plates 392, by an angular distance equal to the angularspacing pitch multiplied by two. Immediately after the valve 530 hasbeen switched to the position corresponding to the second suckingposition, for example, the corresponding rotary plate 392 is rotatedwith the constant-velocity rotary disc 460 with the engaging pin 468still kept in the engaging recess 486. In this condition, the rotaryplate 392 is not pivoted by the stop position changing air cylinder 490.After the pin 468 is disengaged from the recess 486, the cam followerroller 436 is moved into the cam groove 430 a of the concave globoidalcam 410 a and is moved in pressing contact with the downstream sidesurface 442 of the cam groove 430 a under the biasing force of the aircylinder 490, and the rotary plate 392 is stopped at the second suckingposition. Although the width of the non-lead portion 434 of the camgroove 430 a is larger than the diameter of the roller 436, the roller436 will not be oscillated within the width of the non-lead portion 434,since the roller 436 is forced against the downstream side surface 442by the air cylinder 490 through the rotary plate 392. Accordingly, therotary plate 392 can be stopped at the second sucking position with highpositioning accuracy, permitting the component holder head 120 to pickup the electronic component 164 with high reliability. This advantage isalso enjoyed when the rotary plate 392 is stopped at the second suckingposition, and at the first and second mounting positions, permitting theelectronic component 164 to be mounted on the printed-circuit board 38with high positioning accuracy.

After the first one of the predetermined number of the electroniccomponents is picked up from the cartridge 22B by the head 120B, thecartridge support block 20 is further fed by a distance of 8 mm in theforward direction from the position of FIG. 22B, so that the head 120Ccan pick up the second one of the predetermined number of the electroniccomponents from the cartridge 22B, at the first sucking position, asindicated in FIG. 22C.

The electronic component supply device 14 is adapted to change thedirection of feeding of the cartridge support block 20 when all of thepredetermined number of the electronic components have been picked upfrom the most upstream cartridge 22A as seen in the forward feedingdirection P as indicated in FIG. 23A, namely, when all of the electroniccomponents to be mounted on the printed-circuit board 38 have beenpicked up from the cartridges 22. That is, the cartridge support block20 is intermittently moved in a reverse direction as indicated by arrowR in FIG. 23B, namely, in the rotating direction Q of the rotary plates392, so that the electronic components are successively picked up by theheads 120, to be mounted on the next printed-circuit board 38 in theorder which is reversed to that in the case where the cartridge supportblock 20 is intermittently fed in the forward direction P.

In this case where the cartridge support block 20 is fed in the reversedirection R, the electronic components are first supplied from thecartridge 22A, and the heads 120 are normally stopped at the secondsucking position. Initially, the block 20 is fed in the reversedirection R by a distance of 8 mm, and the first one of thepredetermined number of electronic components is picked up from thecartridge 22A by the appropriate head 120, for example, by the head120A, when the rotary plate 392 carries the head 120A is stopped at thesecond sucking position, as shown in FIG. 23B.

When all of the predetermined number of the electronic components havebeen picked up from the cartridge 22A, the cartridge support block 20 isfed by a distance of 8 nm in the reverse direction R, and the rotaryplate 392 (e.g., plate 392E) carrying the head 120 (e.g., 120E) forpicking up the first electronic component from the cartridge 22B isstopped at the first sucking position, so that the electronic componentis picked up by the head 120E at the first sucking position. In thiscase, therefore, the cartridge 22B is moved relative to the head 120E bya distance of 16 mm. The stop position changing valve 530 correspondingto the rotary plate 392E is switched by the valve switching device 536to stop the rotary plate 120E at the first sucking position, when theabove-indicated valve 530 has reached the eleventh angular position.This switching operation of the valve 530 by the valve switching device536 is effected only where the valve 530 has been held in the positioncorresponding to the second sucking position before the valve 530 hasreached the eleventh angular position. After the first one of thepredetermined number of the electronic components has been picked upfrom the cartridge 22B by the head 120E, the block 20 is further fed bya distance of 8 mm in the reverse direction R, as indicated in FIG. 23D,so that the head 120F for picking up the second electronic componentfrom the cartridge 22B may pick up this electronic component at thesecond sucking position.

Thus, the stop position of the rotary plates 392 at the componentsucking position is suitably changed from the first sucking position tothe second sucking position or vice versa, when the cartridge 22 fromwhich the electronic components are picked up by the head 120 is changedfrom one to another. This arrangement is effective to reduce therequired distance of feeding movement of the cartridges 22, permitting adecrease in the time required for the suction nozzles 158 to reach thecomponent sucking position, without increasing the acceleration anddeceleration values of the cartridge support block 20 upon changing ofthe cartridges 22, whereby the components 164 can be picked up andmounted with improved efficiency. Further, since the cartridges 22 canbe fed with reduced vibration, the electronic components 164 containedin the component holder tapes are prevented from taking a verticalposture rather than a horizontal posture in which the components arenormally picked up. In addition, the present arrangement is effective toreduce the required output of the cartridge feed servomotor 26, and therequired strength of the floor or support structure on which theelectronic component mounting system is installed.

After the electronic component is picked up by the head 120 at thecomponent sucking position, the head 120 is rotated toward the componentmounting position through the image taking position. When the electroniccomponent passes the image taking position during movement of the rotaryplate 392 with the constant-velocity rotary disc 460 at a predeterminedconstant velocity, an image of the electronic component is taken by thehigh-speed camera 562 with a stroboscope. Thus, the image of theelectronic component is taken without having to stop the electroniccomponent at the image taking position. The image taking position in thehorizontal direction is fixed irrespective of the selection of the firstor second sucking position, since the image is taken while the rotaryplate 392 is rotated by the constant-velocity rotary disc 460 ratherthan the concave globoidal cam 410.

As described above, the first and second mounting positions areselectively available as the component mounting position at which eachrotary plate 392 is stopped for mounting the electronic component 164 onthe printed-circuit board 38. After one electronic component 164 ismounted, one of the first and second mounting positions is selected sothat the selected mounting position reduces the required distance ofmovement of the printed-circuit board 38 in the X-axis direction forpositioning the board 38 such that the location at which the nextelectronic component 164 is mounted is right below the component holder120 carrying the next electronic component 164. Based on the selectedfirst or second mounting position, the distance of movement of the board38 is determined. This arrangement makes it possible to reduce therequired distance of movement of the printed-circuit board 38 in theX-axis direction, and shorten the required time of movement of thesuction nozzle 158 corresponding to the angular spacing pitch of theheads 120, without increasing the acceleration and deceleration valuesof the board 38. Since the required acceleration and deceleration valuesof the board 38 can be reduced, otherwise possible dislocation of theelectronic components 164 mounted on the board 38 can be avoided, andthe required outputs of the X-axis and Y-axis drive servomotors 42, 48can be reduced.

The kind of the electronic component 164 held by the head 120 of eachrotary plate 392, the location at which the electronic component is tobe mounted, and the first or second sucking position selected for therotary head 392 are known from the component mounting program. If thefirst or second mounting position that should be selected for mountingthe electronic component 164 at the above-indicated location is the sameas the selected first or second sucking position, the stop positionchanging valve 530 corresponding to the rotary plate 392 in question isnot switched by the first valve switching device 534. If the selectedfirst or second mounting position is different from the selected firstor second sucking position, the valve 530 is switched by the first valveswitching device 534 when the valve 530 passes the fifth angularposition of FIG. 18, so that the rotary plate 392 is stopped at theselected first or second mounting position.

If the first or second mounting position selected for a given rotaryplate 392 is different from the first or second sucking position thatshould be selected for the same rotary plate 392 to pick up the nextelectronic component 164, the stop position changing valve 530 isswitched by the second valve switching device 536 when the valve 530passes the eleventh angular position of FIG. 18, so that the rotaryplate 392 can be stopped at the selected first or second suckingposition.

There will next be described the manner of changing the height positionof the component mounting heads 120 at the component sucking andmounting positions and the image taking position.

The present electronic component transferring and mounting apparatus 380is provided with one height changing valve switching device in the formof the third valve switching device 538 which is disposed at the tenthangular position of FIG. 18 as, described above. In other words, theheight position of each head 120 can be changed at one angular positionduring one full rotation of the rotary plate 392 about the main shaft388. Therefore, if the height position is changed to the higher level atthe component mounting position, for example, this higher heightposition or level is maintained at the component sucking and imagetaking positions, or vice versa.

The height of the head 120 at the component mounting position isdetermined or selected in the following manner:

When the electronic component 164 is mounted on the printed-circuitboard 38, the head 120 carrying the electronic component 164 is movedwith the vertical slide 124 with an initial downward movement and thefollowing horizontal movement in the vicinity of the component mountingposition, with the cam follower roller 502 being guided by the camgroove 506 of the stationary cylindrical cam 504, as indicated in FIG.17. The height position of the head 120 during the horizontal movementshould be determined so as to prevent an interference of the electroniccomponent 164 held by the head 120 with the electronic components 164already mounded on the printed-circuit board 38. The possibility of thisinterference decreases with a decrease in the height of the electroniccomponent 164 held by the head 120, and therefore the height position ofthe head 120 can be reduced as the height of the electronic component164 carried by the head decreases. If the height position of the head120 at the component mounting position is fixed at a relatively lowlevel corresponding to an electronic component 164 having a relativelysmall height, another electronic component 164 having a relatively largeheight may interfere with the already mounted electronic components 164.If the height position of the head 120 is fixed at a relatively highlevel corresponding to an electronic component having a relatively largeheight, the vertical stroke of the head 120 required upon mounting of anelectronic component having a relatively small height is undesirablyincreased. Therefore, the height position of the head 120 at thecomponent mounting position is changed in two steps (high and low heightpositions) depending upon the height of the electronic component to bemounted.

The present electronic component mounting system is adapted to deal withthe electronic components 164 whose heights range from 0 mm to 6 mm. Theelectronic components 164 whose heights are 2 mm or smaller will bereferred to as “thin components”, while the electronic components 164whose heights range from 2 mm to 6 mm will be referred to as “thickcomponents”. Where a thick component 164 having the largest height of 6mm has been already mounted on the board 38 and another thick componenthaving the largest height of 6 mm is to be mounted on the board 38, thedistance between the end face of the suction tube 162 of the suctionnozzle 158 and the upper surface of the board 38 should be at least 14mm if an interference of the thick components is avoided by providing aclearance of at least 2 mm between the upper surface of the thickcomponent already mounted on the board 38 and the lower surface of thethick component head by the head 120.

Where a thin component 164 having the largest height of 2 mm and ahighest possibility of interference with the already mounted thickcomponent having the largest thickness of 6 mm is to be mounted on theboard 38, the distance between the end face of the suction tube 162 andthe upper surface of the board 38 should be at least 10 mm if theinterference is avoided by providing the same clearance of 2 mm betweenthe thin and thick components. Hence, the required height difference ofthe head 120 in the above two cases is 4 mm.

In the light of the above analysis, the width or vertical dimension ofthe second wide portion 509 of the cam groove 506 is determined to beequal to a sum of the diameter of the cam follower roller 502 and 4 mm,so that the head 120 may be stopped at different heights at thecomponent mounting position, namely, so that the distance between thesuction tube 162 and the upper surface of the board 38 is 14 mm uponmounting of the thick components, and is 10 mm upon mounting of the thincomponents.

It is noted that the end faces or suction surfaces of the suction tubes162 of all suction nozzles are located on a circle having a center atthe axis of the support shaft 152, and that the suction nozzles 158 fordifferent kinds of the electronic components have the same verticaloperating stroke for sucking and mounting operations.

At the component sucking position, the difference between the high andlow height positions of the heads 120 is 6 mm. As previously explained,the cartridges 22 of the electronic component supply device 14 of thepresent mounting system are adapted such that the electronic components164 are accommodated in component holder tapes whose componentaccommodating recesses are covered by a top covering tape. Eachcomponent holder tape has opposite support portions which define thewidth of the tape and which extend in the longitudinal direction of thetape. The component holder tape further has a component accommodatingportion which is supported by the support portions and which has amultiplicity of component accommodating recesses whose bottom walls takethe form of bosses extending downwards between the support portions. Theelectronic components 164 are accommodated in the respective recesses.This component holder tape is referred to as “embossed type” holdertape. The support portions of the component holder tape are supported bythe body of the cartridge 22. The component accommodating recesses havedifferent depths depending upon the heights of the electronic components164 accommodated therein. However, the support portion of the cartridgebody supporting the support portions of the component holder tape has aconstant height over the entire length of the tape, and the upper openends of all the recesses have the same height, namely, the uppersurfaces of the electronic components 164 accommodated in the recesseshave the same height.

When the electronic component 164 is picked up by the head 120, thesuction tube 162 is first lowered into abutting contact with the uppersurface of the electronic component 164, and is then elevated with theelectronic component held thereon under suction, so that the entirety ofthe electronic component is moved up out of the component accommodatingrecess. The level to which the electronic component is elevated by thehead 120 at the component sucking position is determined so as to avoidan interference of the electronic component with any members surroundingthe cartridge 22, such as a cover member covering the component holdertape, which interference may occur when the rotary plate 392 is rotatedtoward the image taking position. The above-indicated level differsdepending upon the specific cartridge 22 from which the electroniccomponent 164 is picked up. The above level from the level of the uppersurface of the component holder tape is 2 mm for the cartridges 22accommodating the thin components (whose height is 0-2 mm), and is 4 mmfor the cartridges 22 accommodating the thick components (whose heightis 2-6 mm). When the thin component is picked up, therefore, thedistance between the suction tube 162 and the upper surface of thecomponent holder tape is a sum of the above-indicated 2 mm and thelargest height of 2 mm of the thin components, that is, 4 mm. When thethick component is picked up, the above distance is a sum of theabove-indicated 4 mm and the largest height of 6 mm of the thickcomponents, that is, 10 mm. Thus, the difference between these distancesis 6 mm. Accordingly, the width or vertical dimension of the first wideportion 508 of the cam groove 506 of the stationary cylindrical cam 504is made equal to a sum of the diameter of the roller 502 and 6 mm, sothat the head 120 may be stopped at different heights at the componentsucking position, namely, so that the distance between the end face ofthe suction tube 162 and the upper surface of the component holder tapeis 10 mm upon sucking of the thick components, and is 4 mm upon suckingof the thin components.

If the difference of 6 mm of the high and low height positions of thehead 120 selected depending upon the height of the electronic componentto be picked up is maintained at the image taking position, the distancebetween the lower surface of the electronic component and the high-speedcamera 562 may vary by a maximum of 6 mm, and the image of theelectronic component taken by the camera tends to be deteriorated. Toavoid this drawback, the width or vertical dimension of the third wideportion 511 of the cam groove 506 of the cam 504 is determined to beequal to a sum of the diameter of the roller 502 and 3 mm, namely, to besmaller than that of the first wide portion 508 by 3 mm, so as to reducethe amount of variation of the distance between the electronic componentand the high-speed camera 562 for thereby minimizing the deteriorationof the image taken by the camera 562.

The selection of the height position of each head 120 is effectedbetween the component mounting and sucking positions, more specifically,when the height position changing valve 532 corresponding to the head120 whose height should be changed passes the tenth angular position ofFIG. 18. The movement to the tenth angular position of the valve 532 ofthe head 120 whose height should be changed can be detected on the basisof the amount of operation of the main drive servomotor 402. Further,the current high or low height position of the head 120 with respect tothe rotary plate 392, and the high or low height position of that head120 that should be selected at the component sucking and mountingpositions, can be determined according to the component sucking andmounting programs. Based on these information, the height positionchanging valve 532 of each rotary plate 392 is switched by the thirdvalve switching device 538 at the tenth angular position to activate thecorresponding air cylinder 90 to change the height position of thecorresponding head 120, if the currently selected height position isdifferent from the height position that should be selected for the nextelectronic component. If the thin component having a height up to 2 mmis to be mounted, the high height position is selected. If the thickcomponent having a height of 2 mm-6 mm is to be mounted, the low heightposition is selected. The rollers 540, 542 of the third valve switchingdevice 536 are normally placed in their non-operating positions, and oneof these rollers 540, 542 is moved to the operating position to switchthe height changing valve 532, as described above with respect to thefirst and second valve switching devices 534, 536.

The switching of the height position changing valves 532 to select orchange the height position of the heads 120 is effected while the camfollower roller 502 is moved through the horizontal first narrow portion510 of the cam groove 506, which is located upstream of the first wideportion 508 as viewed in the rotating direction of the rotary plate 392,as indicated in FIG. 17. In this arrangement, the roller 502 isprevented from being moved in the first narrow portion 510 in thevertical direction even when the direction in which the roller 502 isbiased by the air cylinder 520 is changed upon switching of the valve532, whereby the cam follower roller 502 is smoothly moved through thefirst narrow portion 510 upon activation of the air cylinder 520 by theheight position changing valve 532. When the roller 502 is biasedupwards against the upper side surface 526, the head 120 is located atits high height position at the component sucking, image taking andcomponent mounting positions. When the roller 502 is biased downwardsagainst the lower side surface 528, the head 120 is located at its lowheight position at the component sucking, image taking and componentmounting positions.

Where the thick electronic component 164 is to be mounted, the head 120at the component sucking position is placed in the high height positionin which the distance between the suction tube 162 and the upper surfaceof the component holder tape is 10 mm, so that the stroke of thevertical movement of the head 120 by the elevating and lowering device260 at the component sucking position is equal to 10 mm plus an expectedpossible vertical positioning error of the apparatus 380 due to somemanufacturing error of associated elements or devices such as those ofthe electronic component supply device 14. Where the thin electroniccomponent 164 is to be mounted, the head 120 at the component suckingposition is placed in the low height position in which theabove-indicated distance is 4 mm, so that the vertical stroke of thehead 120 is equal to 4 mm plus the expected possible verticalpositioning error of the apparatus 380. To obtain these vertical strokesof the head 120, the position of the pivoting axis of the lever 276 ofthe head elevating and lowering device 260 is changed by the head strokeadjusting servomotor 296, to change the vertical stroke of thevertically movable member 266.

Where the head 120 located at the component sucking position is placedin its low height position for picking up the thin component 164, thecam follower roller 502 is moved in the cam groove 506 while it isforced downwards against the lower side surface 528. In this case, thehead 120 is raised by 3 mm when the roller 502 is moved from the firstwide portion 508 into the third wide portion 511, as is apparent fromFIG. 17. That is, the height position of the head 120 when the roller502 is located in the third wide portion 511 or when the head 120 passesthe image taking position or the high-speed camera 562 is 3 mm higherthan that when the roller 502 is located in the first wide portion 508or when the head 120 is located at the component sucking position. Wherethe head 120 located at the component sucking position is placed in itshigh height position for picking up the thick component 164, the roller502 is moved in the cam groove 506 while it is forced upwards againstthe upper side surface 528. In this case, the head 120 located at theimage taking position has the same height as that at the componentsucking position. Thus, the height difference of the head 120 betweenthe high and low height positions at the image taking position isreduced to 3 mm from the height difference of 6 mm at the componentsucking position, so that the tendency of deterioration of the imagequality obtained by the high-speed camera 562 is reduced.

The cam follower roller 502 is then moved into the second wide portion509 through the second narrow portion 514, and the head 120 reaches thecomponent mounting position. Where the high height position of the head120 is selected for the component mounting position, the roller 502 ismoved in rolling contact with the upper side surface 526, so that thehead 120 is stopped at the component mounting position such that thelower end face of the suction tube 162 is spaced 14 mm apart from theupper surface of the printed-circuit board 38, as shown at right in FIG.24. Where the low height position of the head 120 is selected, the head120 is stopped at the component mounting position such that the lowerend face of the suction tube 162 is spaced 10 mm apart from the uppersurface of the board 38, as shown at left in FIG. 24. Thus, there existsa height difference of 4 mm in these two cases. When the thick component164 is mounted on the board 38, the vertical stroke of the head 120 isequal to S1 plus an expected possible vertical positioning error of theapparatus 380 due to some manufacturing error of associated elements ordevices such as those of the device for positioning the board 38. Thevalue S1 is the distance of 14 mm between the lower end face of thesuction tube 162 and the upper surface of the board 38, minus the heightof the component 164. When the thin component 164 is mounted on theboard 38, the vertical stroke of the head 120 is equal to S2 plus thevertical positioning error. The value S2 is the distance of 10 mm minusthe height of the component 164. To obtain these vertical strokes S1,S2, the position of the pivoting axis of the lever 276 of the headelevating and lowering device 260 is adjusted to change the verticalstroke of the vertically movable member 266.

As described above, the height position of the head 120 at the componentmounting position is increased for the thick component 164, and isdecreased for the thin component 164. The high and low height positionsfor the thick and thin components are determined so as to avoid aninterference of the electronic component held by the head 120, with theelectronic components already mounted on the printed-circuit board 38.Further, the present arrangement is effective to reduce the requiredvertical stroke of the head 120 when the thin components are mounted.

It will be understood from the above explanation that the rotary plates70 provide rotary members; the stop position changing air cylinders 490provide circumferential-direction or rotating-direction pressing devicesas part of a circumferential position selecting device; thecircumferential-direction pressing devices cooperate with thecam-follower rollers 436 and the non-lead portions 434 of the camgrooves 430 a, 430 b of the concave globoidal cams 410 a, 410 b toprovide the circumferential position selecting device; and the aircylinders 490, the rollers 436, and the non-lead portions 434 cooperatewith one another to provide an on-path stop position selecting device aswell. In addition, the height position changing air cylinders 520provide axial-direction pressing devices as part of an axial positionselecting device; the axial-direction pressing devices cooperate withthe cam-follower rollers 502 and the first to third wide portions 508,509, 511 of the cam groove 506 of the stationary cylindrical cam 504 toprovide the axial position selecting device; the air cylinders 520, therollers 502, and the wide portions 508, 509, 511 cooperate with oneanother to provide an intersecting-direction stop position selectingdevice or a path selecting device as well. Moreover, the frame 60, thestationary shaft 66, and the groups of bearings 74 cooperate with oneanother to provide a rotary member supporting device; and the concavegloboidal cams 410 a, 410 b as drive cams cooperate with the rollers 436as cam followers to provide a rotary member rotating device. The cams410 a, 410 b and the rollers 436 cooperate with the constant-velocityrotary disc 460 and the engaging devices 464 to provide EC holder headmoving and stopping devices.

Referring next to FIGS. 25-31 and 32A-32D, there will be described anelectronic component mounting system equipped with an electroniccomponent transferring and mounting apparatus 600 constructed accordingto a third embodiment of the present invention.

The electronic component transferring and mounting apparatus 600includes four concave globoidal cams 602 a-602 d similar to the concavegloboidal cams 90 a-90 d provided in the transferring and mountingapparatus 12 of the first embodiment. In the present apparatus 600,however, fifteen rotary plates 604 are rotated by the four concavegloboidal cams 602 a-602 d.

As shown in FIG. 25, a base plate 610 is fixed in a horizontal posture,to top surfaces of a plurality of columns 608 extending upright from abase (not shown). Upper and lower support members 612, 614 are fixed tothe upper and lower surfaces of the base plate 610. The upper and lowersupport members 612, 614 cooperate with the columns 608 and the baseplate 610 to constitute a frame 616 of the present electronic componenttransferring and mounting apparatus 600. The upper and lower supportmembers 612, 614 support a support shaft in the form of a stationaryshaft 618 at their upper and lower ends. The stationary shaft 618extends in the vertical direction through an opening 620 formed throughthe base plate 610. On two axial portions of the stationary shaft 618which are spaced apart from each other in the vertical direction, thereare disposed two arrays 624 of bearings 622. Each array 624 consists offifteen bearings 624. Each of the fifteen rotary plates 604 is supportedthrough a pair of support arms 626 by the corresponding pair of bearings622 one of which belongs to the upper array 624 and the other of whichbelongs to the lower array 624. Thus, the fifteen rotary plates 604 aresupported by the bearings 622 rotatably about a common axis, which isthe axis of the stationary shaft 618. In FIG. 26, the fifteen rotaryplates 604 are shown as being equi-angularly spaced from each otherabout the stationary shaft 618.

The fifteen rotary plates 604 extend through the opening 620 formedthrough the base plate 610 such that the upper portion of each rotaryplate 604 projects upwards from the base plate 610. Each rotary plate604 has a bracket 630 fixed to its upper end, and carries alarge-diameter roller 632 and a small-diameter roller 634 attached toits upper end through the bracket 630 such that the rollers 632, 634 arerotatable about a horizontal axis which extends in a radial direction ofthe stationary shaft 318. These rollers 632, 634 cooperate to constitutea cam follower 636. A support shaft 638 is fixed to the bracket 630. Thelarge-diameter roller 632 is rotatably mounted through a bearing (notshown) on a fixed end portion of the support shaft 638 which is adjacentto the bracket 630, while the small-diameter roller 634 having a smallerdiameter than that of the large-diameter roller 632 is rotatably mountedthrough another bearing on a free end portion of the support shaft 638which is remote from the bracket 630.

As shown in FIG. 26, the four concave globoidal cams 602 a-602 d aredisposed symmetrically with respect to the axis of the stationary shaft618 such that lines of intersection of the outer circumferentialsurfaces of the concave globoidal cams 602 with a plane including axesof all of the concave globoidal cams 602 cooperate to define asubstantially continuous circle which has a center at the axis of thestationary shaft 618. The concave globoidal cams 602 a-602 d arecoaxially mounted on respective rotary shafts 644 a-644 d, as shown inFIGS. 25-27, such that the cams 602 are rotated with the rotary shafts644 and are not axially immovable relative to the rotary shafts 644. Therotary shaft 644 b of the cam 602 b is not shown in these figures. Thefour rotary shafts 644 a-644 d are rotatably supported by respectivepairs of brackets 646 a-646 d through respective bearings.

The concave globoidal cam 602 d will be described in detail by referenceto FIG. 27, by way of example. The rotary shaft 644 d is insertedthrough a bore 652 formed through the concave globoidal cam 602 d, andhas an externally threaded portion 654 at one end thereof, a nut 656screwed on the externally threaded portion 654, and a flange 658 formedat the other end portion. The nut 656 and the flange 658 cooperate tohold the concave globoidal cam 602 d at the opposite ends of the bore652, so that the concave globoidal cam 602 d and the rotary shaft 644 dare not axially movable relative to each other. A rotary motion of therotary shaft 618 is transmitted to the concave globoidal cam 602 dthrough a key 660.

The rotary shaft 644 d is rotatably supported at its opposite ends bythe brackets 646 d through respective bearings 662, 664. The rotaryshaft 644 d is provided with two bevel gears 666, 668 fixed to itsopposite end portions extending from the bearings 662, 664. Portions ofthe brackets 646 d and bearings 662, 664 are accommodated in taperedrecesses 670, 672 formed in the opposite end portions of the concavegloboidal cam 602 d. For the bevel gears 666, 668 of the rotary shaft644 d to mesh with the adjacent bevel gears of the rotary shafts 644 aand 644 c, the bevel gears 666, 668 are required to be located outwardlyof the bearings 662, 664 as viewed in the axial direction of the rotaryshaft 644 d. If the bearings 662, 664 were located axially outwardly ofthe bevel gear 666, 668, it would be difficult to have the bevel gears666, 668 mesh the adjacent bevel gears while avoiding an interferencebetween the bearings 662, 664 and the bearings of the rotary shafts 644a, 644 c.

Like the concave globoidal cam 602 d, the rotary shaft 644 a of theconcave globoidal cam 602 a has bevel gears 676, 678. The bevel gear 678on the side of the cam 206 d meshes with the bevel gear 666. Unlike therotary shafts 644 a, 644 d, each of the rotary shafts 644 b, 644 c ofthe cams 602 b, 602 c has a bevel gear 680, 682 at only one of its ends.The bevel gear 680 of the rotary shaft 644 b meshes with the bevel gear676 of the rotary shaft 644 a, while the bevel gear 682 of the rotaryshaft 644 c meshes with the bevel gear 668 of the rotary shaft 644 d.

The rotary shaft 644 a of the concave globoidal cam 602 a has anextension which extends further from the bevel gear 678 and at which therotary shaft 644 a is rotatably supported by a bracket 690 through abearing 692. The bracket 690 is fixed to the base plate 610. Thisextension of the rotary shaft 644 a has a timing pulley 694 fixedthereto. A rotary motion of a drive source in the form of a main driveservomotor 696 is transmitted to the timing pulley 694 through a timingpulley 698 and a timing belt 700, so that the concave globoidal cam 602a is rotated, whereby the four concave globoidal cams 602 a-602 d arecontemporaneously rotated in synchronization with each other throughmeshing engagement of the bevel gears 666, 668, 676, 678, 680, 682 witheach other. Thus, the rotary shaft 644 a functions as an input shaftwhich receives the rotary motion of the servomotor 696 to rotate thefour concave globoidal cams 602 a-602 d.

The concave globoidal cams 602 a-602 d have respective cam grooves 710a-710 d. Described more specifically, each of the cams 602 has twoidentically shaped cam grooves 710 formed in the outer circumferentialsurface. The cam grooves 710 a of the cam 602 a are illustrated in FIG.28, by way of example. The two cam grooves 710 a are formed with anangular phase difference of 180°, and receive cam followers 636 of thetwo adjacent rotary plates 604.

The concave globoidal cam 602 a is disposed at a position of the baseplate 610 corresponding to the image taking position. Each cam groove710 a has an inclined portion 714 having a lead angle with respect to aplane perpendicular to the axis of the rotary shaft 744 a, and anon-lead portion 716 which does not have such a lead angle and which isperpendicular to the axis of the rotary shaft 644 a. When the rotaryplate 604 is stopped, the inclined portion 714 functions to initiallyaccelerate the rotary plate 604 (which has been rotated at a constantangular velocity) for rotating it over a relatively large angulardistance per unit time, and then decelerating the rotary plate 604 to bestopped at the stop position (i.e., image taking position). When therotary motion of the rotary plate 604 is resumed after a predeterminedtime of stopping at the stop position, the inclined portion 714functions to initially accelerate the rotary plate 604, and thendecelerating it down to the constant angular velocity. The function ofthe inclined portion 714 is the same as that of the inclined portion ofthe concave globoidal cams 62, 410 of the first and second embodiments.The cam grooves 710 d, 710 b of the cams 602 d, 602 b disposed atrespective positions of the base plate 610 corresponding to thecomponent sucking and mounting positions have the same inclined andnon-lead portions as those of the cam grooves 710 a. The cam grooves 710c of the cam 602 c have only an inclined portion, so that the rotaryplate 604 rotated by this cam 602 c is not stopped, and is rotated atthe constant angular velocity.

The cam grooves 710 a, 710 b, 710 c of the concave globoidal cams 602 a,602 b, 602 c are formed such that the appropriate three rotary plates604 reach the image taking. and component mounting and sucking positionsat respective different times, more specifically, such that the pointsof time at which the three rotary plates 604 reach those three stoppositions differ from each other by a time length substantially equal toone third of the time interval at which the fifteen rotary plates 604reach each of those three stop positions. This time interval is therequired time of rotary movement of each rotary plate corresponding tothe angular spacing pitch of the rotary plates 604. In the presentembodiment in which the three stop positions are provided, theabove-indicated time difference of the points of time at which the threerotary plates 604 reach the three stop positions is determined to beequal to one third of the above-indicated time interval. The inclinedportions 714 of the cam grooves 710 a, 710 b, 170c have the same angleof inclination at their curved and straight sections, so that the threecams 602 a, 602 b, 602 c cause the rotary plates 604 to have the samevelocity for the constant velocity movement, and the same accelerationand the deceleration. However, the straight sections of the inclinedportions 714 of the cam grooves grooves 610 a, 710 b, 710 b havedifferent lengths, so that the angular distance between the componentsucking position and the image taking position is different from thedistance between the image taking position and the component mountingposition. This arrangement causes the appropriate three rotary plates604 to reach the image taking and component sucking and mountingpositions at times different from each other by a time substantiallyequal to one third of the time interval corresponding to the angularspacing pitch of the rotary plates 604. The cam groove 710 c of the cam602 c is formed such that the angle of inclination of the inclinedportion 714 is the same as that of the straight sections of the inclinedportions 714 of the cam grooves 710 a, 710 b, 710 d, so that the rotaryplates 604 are rotated by the cam 602 c at the same velocity as thatwhen the rotary plates are rotated by the cams 602 a, 602 b, 602 d.

Referring to FIG. 29, there is shown the cam groove 710 a by way ofexample. Each of the cam grooves 710 a-710 d is a two-step groove havinga wide portion 720 having a relatively large width, and a narrow portion722 which is formed in the bottom surface of the wide portion 720 andwhich has a smaller width than the wide portion 720. The large-diameterroller 632 and the small-diameter roller 634 are held in rollingengagement with the wide portion 710 and the narrow portion 722,respectively.

As shown in FIG. 30, the width of the wide portion 720 is equal to adiameter 2R of the large-diameter roller 632 plus δ₁, while the width ofthe narrow portion 722 is equal to a diameter 2r of the small-diameterroller 634 plus δ₁. The wide and narrow portions 720, 722 have centerlines which are offset from each other by a small distance. The wide andnarrow portions 720, 722 are formed such that the center lines of thewide and narrow portions 720, 722 are offset from each other by adistance of δ₁+δ₂. That is, the center lines of the wide and narrowportions 720, 722 are shifted or offset in the opposite directionsperpendicular to the direction of length of the cam groove 710, by adistance of (δ₁/2+δ₂/2), from the state of FIG. 30 in which one-dotchain line indicates the path of movement of the axes of rotation of therollers 632, 634 and in which there exist clearances of δ₁/2 between therollers 632, 634 and the opposite side surfaces of the wide and narrowportions 720, 722 of the cam groove 710. The value δ₂ indicates anexpected total amount of elastic deformation of the rollers 632, 634,support shaft 638 and side surfaces of the cam grooves 710 a. Therefore,the offset distance of the center lines of the wide and narrow portions720, 722 is equal to (δ₁+δ₂). The large-diameter roller 632 is held inpressing rolling contact with one of the opposite side surfaces of thewide portion 720, while the small-diameter roller 634 is held inpressing rolling contact with the side surface of the narrow portion 722which is opposite to the above-indicated one side surface of the wideportion 720.

The end sections of the cam groove 710 a of the cam 602 a constitute apart of the inclined portion 714, and are inclined with respect to aplane perpendicular to the axis of rotation of the cam 602 a. One of theopposite side wall portions of these end sections which define the widthof the cam groove 710 a has a comparatively small wall thickness and acomparatively low strength. This fact is true for both of the wide andnarrow portions 720, 722 of the cam groove 710 a. The side wall portionhaving the small strength, particularly, of the narrow portion 722, isremoved by cutting, as indicated by solid black areas in FIG. 28, sincethese end sections have a small width and a low strength and may deformdue to a load applied by a cutting tool during cutting of the groove 710or a load applied from the large-diameter and small-diameter rollers632, 634 during movements thereof in the wide and narrow portions 720,722. The above-indicated side wall portion of the end sections of thecam groove 710 a, if left on the cam 602 a, may disturb the rotation ofthe cams 602. The removed side wall portions of the wide and narrowportions 720, 722 are spaced apart from each other in thecircumferential direction of the cam 602 a.

As shown in FIG. 25, the concave globoidal cams 602 a-602 d are coveredby covers 730, 732 fixed to the base plate 610. The cover 730 covers aninner part of the assembly of the cams 602, while the cover 732 coversinner, outer and upper parts of the assembly of the cams 602.

As in the first and second embodiments, each of the fifteen rotaryplates 604 has a vertical slide 740 vertically movably attached thereto.The vertical slide 740 carries a component holder head 742, asschematically shown in FIG. 25 in which the suction nozzle and otherelements are not shown. The selection of the suction nozzles and theoperation to remove the angular positioning error of the electroniccomponent are effected by using the same servomotor as a drive source,as in the previous embodiments.

When the rotary plate 604 is rotated, two cam follower rollers 744 fixedto the vertical slide 740 are moved in rolling engagement with a camgroove 748 formed in a stationary cylindrical cam 746, whereby thevertical slide 740 is vertically moved. The two rollers 744 arerotatably fixed on the vertical slide 740 such that the two rollers 744are spaced apart from each other in the axial direction of thestationary shaft 618. The upper and lower rollers 744 are held inpressing rolling contact at its circumferential surface with the upperand lower side surfaces of the cam groove 748, with a small gap betweenthe upper and lower rollers 744. This arrangement assures smoothvertical movements of the vertical slide 740 without vibration as thevertical slide 740 is rotated relative to the stationary cylindrical cam746. As in the first embodiment of FIGS. 1-12, head elevating andlowering devices similar to the device 260 are provided at positionscorresponding to the component sucking and mounting positions, and adevice for taking an image of the electronic component carried by thehead 742 is provided at a position corresponding to the image takingposition.

When the electronic component is mounted by the present electroniccomponent transferring and mounting apparatus 600, the main driveservomotor 696 is started to rotate the four concave globoidal cams 602a-602 d simultaneously in synchronization with each other. As a result,the fifteen rotary plates 604 are rotated, and stopped at the componentsucking position to pick up the electronic component, at the imagetaking position to obtain the image of the electronic component, and atthe component mounting position to mount the electronic component on theprinted-circuit board 38.

As indicated in the time chart of FIG. 31, the points of time at whichthe appropriate three rotary plates 604 stop at the component sucking,image taking and component mounting positions differ from each other byone third of the required time of rotary movement of each rotary plate604 corresponding to the angular spacing pitch of the rotary plates 604.This arrangement is effective to smooth the load torque of the maindrive servomotor 696, or reduce a variation in the load torque. In thepresent third embodiment in which the fifteen rotary plates 604 areused, the angular spacing pitch is equal to T/15, where T represents therequired time of one full rotation of the rotary plate 604 about theaxis of the main shaft 316. In the time chart, the time is taken alongthe abscissa, while the angle of rotation about the axis of thestationary shaft 618 is taken along the ordinate. In the presentembodiment, thirteen stations are evenly spaced from each other aboutthe axis of the stationary shaft 618. The thirteen stations includethree stations which correspond to the component sucking and mountingpositions and the image taking position. The rotary plates 604 are notstopped at the other ten stations.

FIG. 32A indicates a variation in the load torque of a given concavegloboidal cam 710 when the corresponding rotary plate 604 comes to astop and resumes a rotary motion. The cam 710 is rotated a half turn(through 180°) during a rotary movement corresponding to the angularspacing pitch of the rotary plates 604. During the half turn of the cam710, the corresponding rotary plate 604 is accelerated and deceleratedand is held stopped at the stop position for a half of the predeterminedstop time. During the next half turn, the rotary plate 604 is heldstopped for the remainder of the stop time, and is accelerated anddecelerated to move at a predetermined constant velocity. FIG. 32A showsthe load torque of the cam 710 during one full turn thereofcorresponding to the rotary motions of the two successive rotary plates604 by the cam 710, that is, corresponding to the angular spacing pitchof the rotary plates 604 multiplied by two. The displacement, speed andacceleration of the rotary plates 604 during this time period change asindicated in FIGS. 11A-1, 11A-2 and 11A-3, respectively.

Prior to stopping of the rotary plate 604, the acceleration of therotary plate 604 from the predetermined constant velocity causes apositive load torque to act on the concave globoidal cam 602 since therotary plate 604 tends to rotate at the constant velocity. Thesubsequent deceleration of the rotary plate 604 to be stopped at thestop position causes a negative load torque to act on the cam 602 sincethe rotary plate 604 tends to rotate at the constant velocity. Followingthe stopping of the rotary plate 604, too, the acceleration anddeceleration cause a positive and a negative torque to act on the cam,respectively.

Since the two cam grooves 710 are formed in each of the cams 602 a-602d, one cam follower roller 636 comes into engagement with one of the twocam grooves 710 each time the cam 602 is rotated by a half turn. Namely,the cam follower rollers 636 of the two successive rotary plates 604alternately come into engagement with one and the other of the two camgrooves 710 one after another, during one full turn of the cam 602. Asshown in FIG. 32B, therefore, the phases of two torque variation curvesof the same pattern of the cam 602 corresponding to the two successiverotary plates 604 are offset from each other by 180°. In FIG. 32C, twobroken lines indicate these two torque variation curves of the180°-offset phases, while a solid line indicates a variation in thetotal torque of the cam 602, which is a sum of the load torque valuesrepresented by the load torque variation curves indicated by the brokenlines. As indicated in FIG. 32A, the negative and positive load torquevalues of the cam 602 before and after the stopping of the rotary plate604 symmetrically change with respect to the abscissa. Accordingly, thetorque values of the cam 602 which correspond to the successive rotaryplates 604 and which are represented by the broken lines are partiallyoffset by each other, as indicated by the solid line in FIG. 32C, sincethe rotary motions of the two successive rotary plates 604 have a phasedifference of 180°.

As described above, the points of time at which the rotary plates 604stop at the three stop positions during simultaneous rotations of thefour cams 602 a-602 d by the common main drive servomotor 686 differfrom each other by a time substantially equal to one third of therequired time of movement of each rotary plate 604 corresponding to theangular spacing pitch of the rotary plates 604. Therefore, the loadtorque variation curves of the three cams 602 a, 602 b, 602 d are offsetfrom each other by the time substantially equal to one third of themovement time corresponding to the angular spacing pitch, as indicatedin FIG. 32D, whereby the positive and negative load torque values of thethree cams 602 a, 602 b, 602 d are almost completely offset by eachother, so that the variation in the load torque of the main driveservomotor 696 is effectively reduced.

Since the center lines of the wide and narrow portions 720, 722 of eachcam groove 710 a-710 d are offset from each other, the large-diameterand small-diameter rollers 632, 634 are held in pressing contact withthe opposite side surfaces of the wide and narrow portions 720, 722, asdescribed above. Accordingly, the rollers 632, 634 can smoothly roll inthe wide and narrow portions 720, 722 of the cam groove 710, withoutcausing vibration or noise of the rotary cam 604.

The present apparatus 600 also permits smooth transition of the camfollowers 636 from the cam groove of one of the cams 602 to the camgroove of the adjacent cam 602, without vibration or shock. The oppositeend sections of each cam groove 710 are part of the inclined portion714, which is inclined with respect to the axis of the cam 602. Astraight line connecting the points of contact of the large-diameter andsmall-diameter rollers 632, 634 with the side surfaces of the wide andnarrow portions 620, 722 of the cam groove 710 is inclined with respectto a straight line connecting the open ends of the wide and narrowportions 720, 722 which are open in the end faces of the cam 602.

Accordingly, the large-diameter and small-diameter rollers 632, 634reach the ends of the wide and narrow portions 720, 722 at differenttimes. Namely, when the cam follower 636 is moved from the cam groove ofthe two adjacent cams 602 into the cam groove of the other cam 602, thelarge-diameter roller 632 first reaches the joint or interface betweenthe cam grooves of the adjacent cams 602. Since there exist some gapsbetween the adjacent cam grooves, in particular, due to cutting of theend sections of the wide portion 720, the large-diameter roller 632located at the joint is placed in a released state in which the roller634 is not interposed between the opposite side surfaces of the wideportion 720. At this time, that is, when the large-diameter roller 632is located at the joint of the two cam grooves 710, the small-diameterroller 634 has not reached the joint, and is still interposed betweenthe opposite side surfaces of the narrow portion 722. Since thesmall-diameter roller 634 is thus supported by the narrow portion 722,the large-diameter roller 632 can smoothly transit from from one of thetwo adjacent cam grooves 710 into the other cam groove, withoutvibration. When the small-diameter roller 634 reaches the joint of thetwo cam grooves 710, the large-diameter roller 632 has already beeninterposed between the opposite side surfaces of the wide portion 720 ofthe above-indicated other cam groove 710, whereby the small-diameterroller 634 can smoothly transit into this other cam groove, withoutvibration.

It is noted, in particular, that the cam grooves 710 a-710 d are formedsuch that the rotary plates 604 are moved at the predetermined constantvelocity while the cam followers 636 are located in the opposite endportions of the cams 602 a-602 d. This arrangement assures reducedvibration and shock of the cam followers 636 upon transition thereofbetween the adjacent cams 602, than in the case where the rotary plates604 are accelerated or decelerated while the cam followers 636 arelocated in the opposite end portions of the cams.

As described above, the large-diameter roller 632 and the small-diameterroller 634 are placed in the released state in which the rollers 632,634 are not interposed between the opposite side surfaces of the wideand narrow portions 720, 722 of the cam grooves 710 of the adjacent cams602 when the rollers 632, 634 are moved from one of the cam grooves tothe other. Since one of the rollers 632, 634 is interposed between theopposite side surfaces of one of the adjacent cam grooves, the camfollower 636 can be smoothly moved between the adjacent cam grooves,without shock or vibration.

While each of the cam followers 636 engaging the cam grooves 710 a-710 dof the concave globoidal cams 602 a-602 d used in the third embodimentof this invention consists of the large-diameter roller 632 and thesmall-diameter roller 634, the cam follower 636 may be a tapered roller770 whose diameter continuously decreases in the direction toward thebottom of a cam groove 780 of a concave globoidal cam 778. The taperedroller 770 is rotatably supported through a bearing (not shown) by asupport shaft 776 fixed to a rotary plate 774. In this case, the camgroove 780 is a generally V-shaped groove having a trapezoid shape intransverse cross section.

When the tapered roller 770 is moved from one of the cam grooves 780 ofthe adjacent cams 778 into the other cam grooves, the portion of thetapered roller 770 having a relatively large diameter first reaches thejoint between the two cam grooves, but at this time the portion of thetapered roller 770 having a relatively small diameter does not reach thejoint and is still interposed between the opposite side surfaces of theabove-indicated one cam groove 780, so that the large-diameter portionof the tapered roller 770 can be smoothly moved through the joint. Whenthe small-diameter portion of the tapered roller 770 reaches the joint,the large-diameter portion has been already interposed between theopposite side surfaces of the above-indicated other cam groove 780, thesmall-diameter portion can be smoothly moved into this other cam groove.

The cam follower may be a cylindrical roller having a constant diameter,as indicated at 790 in FIG. 34. In this case, the radially outerportions of the opposite end faces of adjacent concave globoidal cams792, 794 have tapered surfaces 796, 798 which are parallel and adjacentto each other in a plane including the axes of rotation of the cams 792,794. The generators of the tapered surfaces 796, 798 in theabove-indicated plane are inclined in this plane, at selected points onthe generators, with respect to a normal line perpendicular to thecommon axis about which the rotary plates are rotated. The roller 790has an axis of rotation which is perpendicular to the above-indicatedcommon axis and parallel to the above-indicated normal line. When thetapered roller 790 is moved through the joint of the adjacent camgrooves, the circumferential surface portions of different axialportions of the roller 790 reach the joint at different times. When agiven portion of the roller 790 reaches the joint, the other portion isstill interposed between the opposite side surfaces of one of theadjacent cam grooves, so that the roller 790 is not placed in a releasedstate at the joint of the two cam grooves, whereby the roller 790 can besmoothly moved into the other cam groove.

Movable members may be moved by a combination of a concave globoidal cam810 and a cylindrical cam 812, as shown in FIG. 35. In this case, too,suitable means may be provided for preventing a cam follower from beingplaced in the released state at the joint of adjacent cam grooves. Themovable members are rotated by rotation of the concave globoidal cam810, about an axis which is perpendicular to a plane including axes ofrotation P, Q of the cams 810 and 812 and which passes a center of acircular arc which is defined by a line of intersection between theabove-indicated plane and the circumferential surface of the globoidalcam 810. Then, the movable members are linearly moved by rotation of thecylindrical cam 812 in a direction parallel to the axis of rotation Q ofthe cylindrical cam 812. In this arrangement, such means as provided inthe illustrated embodiments may be used for preventing the releasing ofthe cam follower at the joint of the adjacent cam grooves. For instance,the means may include the provision of two-step cam grooves having awide portion and a narrow portion, and the provision of cam followerseach including a large-diameter portion and a small-diameter portion.The combination of cams need not be a combination of a single concavegloboidal cam and a single cylindrical cam. Namely, the combination mayconsist of at least one concave globoidal cam and at least onecylindrical cam, which cooperate to move movable members along a desiredpath such as a path like a track defined by two opposite parallelstraight lines and two circular arcs connecting the ends of the parallelstraight lines.

In the second embodiment shown in FIGS. 13 to 24, the two selectablecomponent mounting positions where the component holder heads 120 canmount electronic components (“ECs”) on a printed circuit board (“PCB”)38 is determined such that the holder heads 120 can freely mount the ECson the PCB 38, without being interfered with by the ECs which havealready been mounted on the PCB 38, irrespective of whether the ECsmounted on the PCB 38 may be large or small. However, as shown in FIG.37, the two selectable component mounting positions may be determinedsuch that at the higher one of the two mounting positions the holderheads 120 can prevent interference with large ECs 900 mounted on the PCB38 and at the lower mounting position the holder heads 120 to canprevent interference with small ECs 902 mounted on the PCB 38. Forexample, in the case where the PCB 38 has a large-EC mounting area formounting a group of large ECs 900 and a small-EC mounting area formounting a group of small ECs 902, the two component mounting positionseach of which corresponds to the lower ends of respective componentsuction nozzles 904 of the holder heads 120 may be determined atdifferent height positions, P₁ and P₂, respectively.

The “large” ECs 900 may comprise ECs 900 in different larger sizes. Inthis case, a height, h₁, shown in FIG. 37 indicates the height of thelargest-size EC 900. The height position P₁ of the higher mountingposition (i.e., the stroke of vertical movement of each suction nozzle904) may be adjusted depending upon the height h₁. Similarly, the“small” ECs 902 may comprise ECs 902 in different smaller sizes. In thiscase, a height, h₂, shown in FIG. 37 indicates the height of the largestEC 902 of the small-size ECs 902. The height position P₂ of the lowermounting position may be adjusted depending upon the height h₂. It ispreferred to provide a clearance, L₁, between the ECs 900, 902 mountedon the PCB 38 and the EC 900, 902 held by the suction nozzle 904.

The size-different ECs which belong to each of the above-indicatedlarge-size and small-size EC groups can be mounted by using differentsorts of suction nozzles 904 having different axial lengths. Since therespective distances between the axis line of the support shaft 152 andthe respective free end faces (i.e., suction openings) of the differentsuction nozzles 904 differ from each other, each of the size-differentECs can be mounted by using a corresponding one of the suction nozzles904 which has an appropriate distance between the axis line of the shaft152 and the free end face of the one nozzle 904.

In addition, as shown in FIG. 38, the height position of the componentsuction nozzles 904 may be determined at a lower position, P₃, formounting the large ECs 900, and may be determined at a higher position,P₄, for mounting the small ECs 902. For example, in the case where agroup of large ECs 900 are mounted before a group of small ECs 902 suchthat the path along which the large ECs 900 are sequentially mounted onthe PCB 38 does not intersect itself, there is no possibility that theEC held by each suction nozzle 904 be interfered with by the ECs mountedon the PCB 38. Therefore, the height position of the component suctionnozzles 904 may be determined at the lower position P₃, for mounting thelarge ECs 900. When the small ECs 902 are mounted after the large ECs900, the component suction nozzles 904 are positioned at the higherposition P₄, for preventing interference with the large ECs mounted onthe PCB 38. In this case, the mounting apparatus 380 can freely mountthe small ECs 902 on the PCB 38.

In the case where the path along which the large and/or small ECs 900,902 are mounted on the PCB 38 is so determined not to intersect itself,the height position of the component suction nozzles 904 may bedetermined, as shown in FIG. 39, at a higher position, P₅, equal to thesum of the above-defined height h₁ and clearance L₁, for mounting thelarge ECs 900, and may be determined at a lower position, P₆, equal tothe sum of the above-defined height h₂ and clearance L₁, for mountingthe small ECs 902.

In the case where the component holder heads 120 are stopped at thehigher one of the two selectable component sucking positions and at thelower one of the two selectable component mounting positions, or viceversa, the height position of each holder head 120 may be changed whilethe holder head 120 is moved from the sucking position to the mountingposition. For example, the cam groove 506 of the stationary cylindricalcam 504 may include a horizontal narrow (not wide) portion between theimage taking position and the component mounting position, and aheight-position-changing-valve switching device may be provided inassociation with the narrow portion for pressing the cam-follower roller502 connected to each head holder 120, against the other side surface ofthe wide portion of the cam groove 506. This is also true for the casewhere the holder heads 120 are stopped at the higher one of the twoselectable component sucking or mounting positions and at the lower oneof the two selectable image taking positions, or vice versa.

In the second embodiment shown in FIGS. 13 to 24, the component holderheads 120 are moved up and down by the stationary cylindrical cam 504having the cam groove 506, and the height position of the holder heads120 is changed in the two steps by selectively pressing the rollers 502against each of the upper and lower side surfaces 526, 528 of the camgroove 506. However, as shown in FIG. 40, the apparatus 380 may employ,in place of the cam 504, a stationary cylindrical cam 910 having a camridge or rib 912 with which a pair of rollers 916 as cam followers whichare provided on an elevator plate 914 of each rotary plate 70 areengageable.

The cam rib 912 includes a thick portion 918, and three thin portions920 (only one 920 is indicated at broken line in FIG. 40). The thicknessor dimension of the thick portion 918 in a direction (hereinafter,referred to as the “axial direction”) parallel to the axis line aboutwhich the rotary plates 70 supporting the component holder heads 120 arerotatable, is slightly greater than the distance between the pairedrollers 916. The three thin portions 920 correspond to the componentsucking, image taking, and component mounting positions, respectively,and the thickness of each thin portion 920 in the axial direction issmaller than the distance between the paired rollers 916, so that therollers 916 are permitted to be moved in the direction of the thicknessof the think portion 920. In addition, the cam rib 912 includes at leastone portion (not shown) whose position in the axial directioncontinuously changes, so that the two selectable component suckingpositions are higher than the two selectable component mountingpositions. The elevator plate 914 is moved up and down by one or moreheight position changing air cylinders (not shown) provided between theelevator plate 914 and the corresponding rotary plate 70, so that aselected one of the two rollers 616 is pressed against a correspondingone of upper and lower side surfaces 922, 924 of the cam rib 912.

In addition, each of the concave globoidal cams 410 a, 410 b may have acam rib including a thick and a thin portion and each of the rotaryplates 70 may have a pair of rollers as cam followers which areengageable with the cam rib. In this case, the thin portion has athickness which permits the pair of rollers to be moved in the directionof rotation of the rotary plates 70 about the stationary shaft 66.

The principle of the present invention applied to the apparatus 380shown in FIGS. 13-24 may be applied, as shown in FIG. 41, to an ECmounting system including a table 930 which is intermittently rotatableabout an axis line and a plurality of EC holder heads 932 which aresupported by the rotatable table 930 such that the holder heads 932 areequiangularly spaced from each other in a rotating direction of thetable 930. That is, the stop position of the holder heads 932 at a stopstation is changed selectively in two steps in the rotating direction.The table 930 has the same number of part-annular guide grooves 934 asthat of the holder heads 932, such that the guide grooves 934 have acommon center at the stationary shaft 66 and are equiangularly spacedfrom one another. Each holder head 932 is supported by a rotary member936 to which a pair of guide rollers 938 are fixed such that each of theguide rollers 938 is rotatable about an axis line parallel to the axisline about which the table 930 is rotatable. The guide rollers 938 arerotatably fit in the corresponding guide groove 934. Thus, the rotarymember 936 is guided by the guide groove 934 via the rollers 938. Apiston rod 942 of a rotating-direction position changing air cylinderdevice 940 which is rotatably attached to the rotatable table 930 isrotatably connected to the rotary member 936. When the piston rod 942 isprojected from, and retracted into, a housing of the cylinder device940, the rotary member 936 is moved along a circular arc having a centerat the rotation axis line of the table 930, so that the stop position ofthe holder head 932 is changed between a first position corresponding toone of opposite ends of the guide groove 934 with which one of the guiderollers 936 is engaged, and a second position corresponding to the otherend of the guide groove 934 with which the other roller 936 is engaged.

In addition, the principle of the present invention applied to theapparatus 380 shown in FIGS. 13-24 may be applied, as shown in FIG. 42,to an EC mounting system wherein a component holder head (not shown) ismoved along a straight movement path for sucking and mounting an EC.That is, the holder head can take a selected one of two positions whichare spaced from each other in a direction perpendicular to the straightmovement path, e.g., a vertical direction. A nut 954 is fixed to amovable member 950 on which the component holder head is mounted, and isscrewed on a ball screw 956 which is coupled to a servomotor (notshown). When the screw 956 is driven or rotated by the servomotor, themovable member 950 is linearly moved by being guided by a pair of guiderails 958.

A guide rail 962 is provided on a vertical side surface 960 of themovable member 952, and an elevator member 964 is fit on the guide rail962 such that the elevator member 964 is movable up and down. Thecomponent holder head (not shown) is mounted on the elevator member 964such that the holder head is movable up and down and is rotatable aboutits axis line, and is moved up and down by a holder-head elevating andlowering device (not shown) and rotated by a holder-head rotating device(not shown). The elevator member 964 has an arm which extends from oneside of the movable member 950 to the opposite side thereof over theupper surface thereof. A roller 966 as a cam follower is attached to afree end of the arm of the elevator member 964, such that the roller 966is rotatable about a horizontal axis line perpendicular to the directionof movement of the movable member 950. The roller 966 is rotatably fitin a cam groove 970 of a stationary cam 968. The stationary cam 968extends along the movement path of the movable member 950, and the camgroove 970 includes at least one narrow portion 972, and three wideportions 974 (only one 974 is indicated at broken line) corresponding toan EC sucking position, an image taking position, and an EC mountingposition, respectively. The narrow portion 972 has a small width inwhich the roller 966 is fit with only small clearances lefttherebetween. Each wide portion 974 has a great width which permits theroller 966 to be moved in the direction of the width. The cam groove 970additionally includes, between the narrow and wide portions 972, 974, aportion whose width continuously changes.

A piston rod 980 of a normal-direction stop position changing aircylinder device 978 provided on the movable member 950 is connected tothe horizontal arm of the elevator member 964. When the piston rod 980is extended from, and retracted into, a housing of the cylinder device978, the cam-follower roller 966 is pressed against a selected one of anupper side surface 982 and a lower side surface 984 of the cam groove970, so that the elevator member 964 is moved up and down. In this way,the height position of each of the component holder heads 120 can bechanged in two steps at the component sucking position, the image takingposition, and the component mounting position.

The cam groove 970 may include at least one portion whose heightposition continuously changes, so that the height position of eachholder head 120 at one or two of the component sucking and mountingpositions and the image taking position may differ from those or that ofthe same 120 at the other positions or position.

While the presently preferred embodiments of the present invention havebeen described above in detail, it is to be understood that theinvention is not limited to the details of the illustrated embodiments,but may be otherwise embodied.

In the illustrated embodiments, the component holder head 120, 742provided on the vertical slide 124, 740, 914 are vertically movedtogether with the vertical slide 124, 740, 914, by the verticallymovable member 266 provided in the stationary cylindrical cam 128, 504,746, at each of the component sucking and mounting positions (i.e., stoppositions). However, members for vertically moving the heads 120, 740need not be part of the stationary cam. For instance, the componentholder head may be fixed to the vertical slide while the vertical slideis vertically moved by vertically moved by the stationary cam, and maybe vertically moved relative to the vertical slide at each of thecomponent sucking and mounting positions where the locking of the holderhead to the vertical slide is released. Even in the latter case, theapparatus 380 as the second embodiment shown in FIGS. 13-24 may maintainthe technical feature that the height position of the heads 120 at eachof the component sucking, image taking and component mounting positionsis selectable from two or more height positions.

Like the apparatus 380 of FIGS. 13-24, the apparatus 12 of FIGS. 1-12and the apparatus 600 of FIGS. 25-32 may be adapted such that each ofthe component sucking and mounting positions is selectable from two ormore circumferential positions. In addition, or alternatively, theapparatus 12, 600 may be adapted such that the height position of theheads 120, 742 at each of the component sucking, image taking andcomponent mounting positions is selectable from two or more heightpositions.

Further, the apparatus 12 of FIGS. 1-12 and the apparatus 600 of FIGS.25-32 may be adapted such that the images of the electronic components164 held by the suction nozzles 158 under suction are obtained withoutstopping the rotary movements of the rotary plates 70, 604, as in theapparatus 380 of FIGS. 13-24. In this case, a high-speed camera with astroboscope or a device including for example a line sensor capable ofobtaining images of the electronic components 164 in motion is providedat the image taking position, and the cam groove 92 d, 710 a of theconcave globoidal cams 90 d, 602 a disposed at the image taking positionare formed so that the rotary plates 70, 604 are rotated continuously,without stopping at the image taking position. The height position ofthe head 120 while the head 120 passes the image taking position may bechanged in at least two steps, or may not be changed (may be heldconstant).

In the second embodiment of FIGS. 13-24, the stop position (i.e.,circumferential position) changing air cylinders 490 and the heightposition changing air cylinders 520 are controlled by mechanicallyswitching the stop position (i.e., circumferential position) changingvalves 530 and the height position changing valves 532. However, thesevalves 530, 532 may be replaced by solenoid-operated valves, which maybe switched on the basis of output signals of sensors which detect thepassing of each rotary plate 392 through predetermined positions.Alternatively, the position of each rotary plate 392 may be determinedon the basis of the amount of rotation of the main drive servomotor 402or the angular position of the main shaft 388, and the solenoid-operatedvalves may be switched when the determined position of the rotary plate392 coincides with the predetermined positions, more precisely, at thepositions where the stop positions (i.e., circumferential positions) atthe component sucking and component mounting positions should bechanged, and at the positions where the height positions at thecomponent sucking, image taking, and component mounting positions shouldbe changed.

Further, the air cylinders 544, 546 used for the first, second and thirdvalve switching devices 534, 536, 538 may be replaced by solenoidsadapted to move the rollers 540, 542 for switching the stop position(i.e., circumferential position) changing valves 530 and the heightposition changing valves 532.

In the second embodiment of FIGS. 13-24, the high height positions ofthe heads 120 are selected at the component sucking, image taking andcomponent mounting positions, when the electronic component 164 has arelatively large height, and vice versa. However, the high and lowheight positions of the heads 120 may be selected when the electroniccomponents 164 have relatively small and large heights, respectively. Inthis case, for example, all of the relatively thick electroniccomponents are first mounted on the printed-circuit board in apredetermined order, from one end of the board in the X-axis direction,and then the relatively thin electronic components are mounted atrandom. The mounting of the relatively thick electronic components doesnot cause any interference between the components to be mounted and thecomponents already mounted on the board, since the relatively thickcomponents are all mounted first in the predetermined order in onedirection. Therefore, the height position of the heads 120 can bereduced during mounting of the relatively thick components. During themounting of the relatively thin components, on the other hand, theheight position of the heads 120 is made high enough to avoid aninterference between the components to be mounted and the alreadymounted components. The height position of the heads 120 may be madecomparatively low for all the electronic components, if the componentsare all mounted in the predetermined order from one end of theprinted-circuit board in the predetermined one direction.

In the second embodiment of FIGS. 13-24, only one switching device 538for switching the height position changing valves 532 is provided at thetenth angular position of FIG. 18 corresponding to the first narrowportion 510 between the component mounting and sucking positions. Inthis arrangement, if the high height position of the heads 120 isselected for the component sucking position, for example, the highheight position is also selected for the image taking and componentmounting positions. However, another switching device for switching theheight position changing valves 532 may be provided at a suitableposition, for instance between the component sucking and image takingpositions. In this case, the cam groove 506 of the stationarycylindrical cam 504 has a third narrow portion between the first andthird wide portions 508, 509. According to this arrangement, the lowheight position of the heads 120 may be selected at the image taking andcomponent mounting positions even if the high height position isselected at the component sucking position.

The illustrated embodiments are adapted such that the twelve or fifteenrotary plates 70, 392, 604 are stopped at three or two stop positions.However, the number of the rotary members and the number of the stoppositions (and the kinds of the stop positions) may be suitablydetermined.

In the illustrated embodiments, the rotary members in the form of therotary plates are equi-angularly spaced from each other at apredetermined angular interval about the axis of the stationary shaft 66or main shaft 388, 618. However, it is possible that some of the rotarymembers are spaced from each other at a first angular interval, whilethe other rotary members are spaced from each other at a second angularinterval different from the first angular interval.

The rotary plates 70, 392, 604 have a relatively smaller thickness attheir inner end portions as viewed in radial directions of thestationary or main shaft 66, 388, 618, in order to avoid an interferencebetween the adjacent rotary plates. However, the interference may beavoided by increasing the radial distance between the inner ends of therotary plates and the axis of the stationary or main shaft.

The illustrated electronic component transferring and mounting apparatusand electronic component mounting system are adapted to transfer andmount various electronic components whose heights are not larger than 6mm, the principle of the present invention is equally applicable to suchapparatus and system capable of transferring and mounting electroniccomponents whose heights are greater than 6 mm.

In the embodiments shown in FIGS. 13-24 and 36 to 42, the variouselectronic components are grouped into the two groups, i.e., the smallcomponents whose heights are not greater than 2 mm and the largecomponents whose heights are greater than 2 mm and not greater than 6mm. However, the criterion of 2 mm may be replaced by 3 mm or any otherappropriate height. The component holder head positioning apparatus inaccordance with the present invention is applicable to various componenttransferring and mounting apparatuses or various component mountingsystems.

The component holder heads 120, 742 in the illustrated embodiments maybe provided with a positioning device for locking the nozzle holder 154after one of the six suction nozzles 158 is placed in its operatingposition. In this case, the positioning device may include a positioningpin engageable with a selected one of six positioning holescorresponding to the six suction nozzles 158. The positioning holes maybe tapered holes which are formed in one of the nozzle holder 154 andthe stationary support shaft 152 rotatably supporting the nozzle holder154, such that the tapered holes are equi-angularly spaced from eachother in the circumferential direction of the nozzle holder 154 orsupport shaft 152. In this instance, the positioning pin is provided onthe other of the nozzle holder 154 and the stationary support shaft 152,and is biased by suitable biasing means toward a position for engagementwith the selected positioning hole. When one of the six suction nozzles158 is selected, the positioning pin is disengaged from the positioninghole against the biasing force of the biasing means, to permit therotation of the nozzle holder 154 relative to the stationary supportshaft 152. A plurality of positioning pins may be provided so that aselected one of these pins is engageable with a single positioning hole.

In the third embodiment of FIGS. 25-32, the center lines of the wide andnarrow portions 720, 722 of the cam groove 710 are offset from eachother. This offset arrangement is not essential. Namely, the centerlines of these wide and narrow portions 720, 722 may be aligned witheach other.

Where the rotary plates are rotated by only the concave globoidal camsas in the first and third embodiments of FIGS. 1-12 and FIGS. 25-32, thenumber of the concave globoidal cams is not limited to four. That is,three or smaller or five or more concave globoidal cams may be used.

In the illustrated embodiments, the application of the vacuum pressureto the suction nozzles 158 is electrically controlled by switchingdevices including solenoid-operated directional control valves. However,the application of the vacuum pressure may be mechanically controlled.For instance, each of the members which are movable with the componentsuction nozzles, such as the rotary members (rotary plates), is providedwith a component-suction-nozzle-related switching device having aswitching member which is movable between a vacuum supply position inwhich the switching device permits vacuum to be supplied to the suctionnozzle and a vacuum cut position in which the switching device does not.Additionally, a component-sucking-position-related switching devicewhich moves the switching member from the vacuum cut position to thevacuum supply position and thereby switches thecomponent-suction-nozzle-related switching device is provided at thecomponent sucking position, and a component-mounting-position-relatedswitching device which moves, after the mounting of the electroniccomponent on the printed circuit board, the switching member from thevacuum supply position to the vacuum cut position and thereby switchesthe component-suction-nozzle-related switching device is provided at thecomponent mounting position.

In the second embodiment of FIGS. 24-32, switching devices may beprovided on the constant-velocity rotary disc 460. The switching memberof each switching device is moved to the vacuum supply position by asuitable actuator device which is disposed at a position correspondingto the component sucking position. The actuator device is activated tomove the switching member to the vacuum supply position, insynchronization with the downward movement of the component holder headby the head elevating and lowering device 260. Another actuator deviceis disposed at a position corresponding to the component mountingposition.

This actuator device is actuated to move the switching member to thevacuum cut position, in synchronization with the downward movement ofthe head by the head elevating and lower device 260. The switchingmember is arranged to be held in the vacuum supply or cut position oncethis position is established.

Where the application of the vacuum pressure to the suction nozzles ismechanically controlled, too, the vertical stroke of the verticallymovable member of each head elevating and lowering device 260 is reducedto the minimum value in the event of a failure of the suction nozzles tonormally pick up the electronic component. This arrangement prevents acontact of the electronic component or suction tube with theprinted-circuit board, and a movement of the switching member of theswitching device to the vacuum cut position by the actuator devicedisposed at the position corresponding to the component mountingposition, whereby the electronic component erroneously picked up by thesuction nozzle is not mounted on the printed-circuit board. A furtheractuator device is provided at a position corresponding to the componentdiscarding area, so that the switching member of the switching device ismoved to the vacuum cut position to release the electronic componentfrom the suction nozzle when the switching device has reached theposition of the actuator device in the component discarding area. Theswitching member of the switching device is also moved to the vacuum cutposition when the component holder head fails to pick up the electroniccomponent.

The illustrated embodiments are adapted such that the downward movementof the component holder head is initiated before the correspondingrotary plate is stopped at the component sucking and mounting positions,and such that the rotary movement of the rotary plate is initiatedbefore the head reaches its upper stroke end after the sucking ormounting of the electronic component. Thus, the rotary movement and thevertical movement of the head take place contemporaneously, whereby therequired time of movement of each head corresponding to the angularspacing pitch of the heads can be reduced, with a result of improvingthe component mounting efficiency. However, the contemporaneous rotaryand vertical movements of the head is not essential. Namely, the headmay be moved down only after the rotary plate has been brought to thecomponent sucking and mounting positions, and the rotary plate may berotated only after the head has been moved to its upper stroke end.

In the third embodiment of FIGS. 25-32, each rotary plate is stopped atthree stop positions, and the points of time at which the three rotaryplates corresponding to the three stop positions are stopped at thesethree stop positions differ from each other by a time length equal toone third of the required time of movement of the rotary platescorresponding to the angular spacing pitch of the rotary plates, so thatthe positive and negative values of the load torque of the three concavegloboidal cams are at least partially offset by each other. In the thirdembodiment in which each rotary plate is stopped at the three position,the above-indicated time length (time difference of the above-indicatedpoints of time) is determined to be equal to one third of the requiredtime of rotary movement of each rotary plate corresponding to theangular spacing pitch of the rotary plates. However, the above-indicatedtime length (time difference) may be equal to one fourth of the requiredtime of rotary movement corresponding to the angular spacing pitch ofthe rotary plates, if each rotary plate is stopped at four stopposition. Namely, the time difference decreases with an increase in thenumber of the stop positions. As the time difference decreases, theeffect of offset of the positive and negative load torque values of theconcave globoidal cams or main drive servomotor is increased.

In the first embodiment of FIGS. 1-12, the rotary plates 70 aresupported by the stationary shaft 66 which is not rotated. However, thestationary shaft 66 may be replaced by a rotary shaft which is rotatedwith the rotary plates 70. In this case, the rotary shaft is rotated bythe main drive servomotor provided for rotating the concave globoidalcams. The rotary shaft has a vacuum passage which is connected to thevacuum source through a conduit and a rotary joint, and is connectedthrough hoses to vacuum switching devices corresponding to the rotaryplates.

In the first embodiment, the rotary valve provided on the stationaryshaft 66 for connecting the vacuum passage in the stationary shaft 66 tothe switching devices 178 is driven by an exclusive drive source.However, the rotary valve may be rotated with one of the rotary plates.

In the illustrated embodiments, the vacuum switching devices forapplying the vacuum pressure to the suction nozzles of the componentholder heads are rotated with the component holder heads. However, theswitching devices may be provided on a stationary member. The switchingdevices are connected to the suction nozzles of the respective componentholder heads through suitable passages, rotary valve and hoses, asdescribed above.

The component holder positioning apparatus embodied as the apparatus 380shown in FIGS. 13-24, 36 or the apparatuses shown in FIGS. 37-40 may beemployed by an electronic component mounting system including anelectronic component transferring apparatus as disclosed in the Japanesepatent publications JP-A-6-77693 and JP-A-6-45787. In the electroniccomponent transferring apparatus of this system, a plurality ofcomponent holder heads are disposed at a predetermined angular intervalon a rotary table which is continuously rotated at a constant velocity,and the heads that should be stopped at the predetermined stop positionssuch as the component sucking and mounting positions are rotated aboutthe axis of the rotary table at the same velocity in the directionopposite to the direction of rotation of the rotary table, so that thoseheads are virtually stopped at the stop positions.

In the embodiments shown in FIGS. 13-24, 36-39, 41, and 42, the camgroove of the stationary cam 504, 968 or the drive (concave globoidal)cam 410 may be adapted to engage a pair of rollers as cam followerswhich are connected to each of the component holder heads 120, like therollers 744 employed in the third embodiment shown in FIG. 13. The tworollers are provided at different positions, respectively, in thedirection of width of the cam groove. The cam groove includes at leastone narrow portion whose width is slightly shorter than the distancebetween the two rollers plus the respective diameters of the tworollers, so that the two rollers are fit in the narrow portion withoutany spaces left therebetween. The cam groove additionally includes atleast one wide portion whose width is greater than that of the narrowportion and which permits the two rollers to be moved in the directionof the width. In this case, when the two rollers are moved through thenarrow portion of the cam groove, the component holder head iseffectively prevented from being out of position in the direction ofwidth of the cam groove.

In the embodiments shown in FIGS. 13-24, 36-39, 41, and 42, the camgroove of the stationary cam 504, 968 includes both the narrow and wideportions. However, it is not essential that the cam groove include atleast one narrow portion. That is, the cam groove may consists of only asingle wide portion or a plurality of wide portions which permits orpermits one or two cam followers to be moved in the direction of widthof the groove. This is also true in the case where the stationary camhas, in place of a cam groove, a cam ridge or rib like the cam rib 912shown in FIG. 40.

In the embodiments shown in FIGS. 13-24 and 36-42, the two selectablestop positions (i.e. circumferential positions) are provided at each ofthe component sucking and mounting positions (i.e., stop stations), andthe two selectable height positions (i.e. axial positions spaced fromeach other in the axial direction of the stationary shaft 388perpendicular to the circular movement path of the rotary members 392)are provided at each of the component sucking, image taking, andcomponent mounting positions. However, three or more selectablecircumferential positions may be provided at at least one of the stopstations, and three or more selectable axial positions may be providedat at least one station which may comprise one or more of the componentsucking, image taking, and component mounting positions.

In the first embodiment shown in FIGS. 1-12 or the third embodimentshown in FIGS. 25-42, the rotary plates are not stopped at the imagetaking position. However, the apparatus 12, 600 may be modified suchthat the rotary plates are not stopped at the image taking position.That is, an image of an electronic component is taken while thecomponent is moved through the image taking position. In either case,the height position of the component holder heads may be changed in twoor more steps at the image taking position.

In the illustrated embodiments, each of the component suction nozzles158 is provided with the reflector to plate 163. However, the reflectorplates 163 may be replaced by luminous plates.

The component suction nozzles 158 may be replaced by chucks each ofwhich includes two pairs of grasping hands one pair of which are openedand closed in a first direction and the other pair of which are openedand closed in a second direction perpendicular to the first direction.

It is further noted that the present invention is not limited to anelectronic component holder head positioning apparatus or an electroniccomponent transferring apparatus which is employed by an electroniccomponent mounting system adapted to transfer electronic components andmount them on an object such as a printed-circuit board, and that theprinciple of the present invention is also applicable to an electroniccomponent holder head positioning apparatus or an electronic componenttransferring apparatus adapted to simply transfer electronic componentsfrom a given device to another device.

It is also noted that the present invention may be embodied with variousother combinations of the elements employed in the illustratedembodiments.

It is to be understood that the present invention may be embodied withvarious other changes, modifications and improvements, which may occurto those skilled in the art, in the light of the foregoing teachings,without departing from the scope of the invention defined in thefollowing claims.

What is claimed is:
 1. An apparatus for selectively positioning at leastone electronic component holder head for holding an electroniccomponent, at a selected one of a plurality of selectable positions ofat least one stop station, comprising: a holder head moving and stoppingdevice which moves the electronic component holder head along apredetermined movement path and stops the holder head at said at leastone stop station on the movement path; and at least one of (a) at leastone on-path stop position selecting actuator which moves said at leastone electronic component holder head to one of a plurality of firston-path stop positions thereof which are spaced from each other on themovement path, and thereby selects, as one of the selectable positionsof the stop station, a corresponding one of a plurality of secondon-path stop positions which are spaced from each other on the movementpath and which have a same position in a direction perpendicular to themovement path, so that the holder head moving and stopping device stops,and thereby positions, the electronic component holder head at theselected one second on-path stop position as the selected one selectableposition of the stop station, and (b) at least oneintersecting-direction stop position selecting actuator which moves saidat least one electronic component holder head to one of a plurality offirst intersecting direction stop positions thereof which are spacedfrom each other in a first direction intersecting the movement path, andthereby selects, as one of the selectable positions of the stop station,a corresponding one of a plurality of second intersecting-direction stoppositions which are spaced from each other in the first directionintersecting the movement path and which have a same position in asecond direction perpendicular to the first direction, so that theholder head moving and stopping device stops, and thereby positions, theelectronic component holder head at the selected one secondintersecting-direction stop position as the selected one selectableposition of the stop station.
 2. An apparatus according to claim 1,further comprising a movable member which supports the electroniccomponent holder head such that the holder head is movable in adirection intersecting the movement path and which is movable along themovement path; a stationary cam having a cam groove extending along themovement path; a cam follower which is connected to the movable membersuch that the cam follower is movable with the holder head and which isengageable with the cam groove of the stationary cam, at least a portionof the cam groove having a width which permits the cam follower to bemoved in a direction of said width, and wherein theintersecting-direction stop-position selecting device comprises anintersecting-direction pressing device which selectively presses the camfollower against each of a pair of opposed side surfaces of the camgroove.
 3. An apparatus according to claim 1, further comprising amovable member which supports the electronic component holder head suchthat the holder head is movable in a direction intersecting the movementpath and which is movable along the movement path; a stationary camhaving a cam rib extending along the movement path; a pair of camfollowers which are connected to the movable member such that the pairof cam followers are movable with the holder head and which areengageable with the cam rib of the stationary cam, at least a portion ofthe cam rib having a thickness which permits the pair of cam followersto be moved in a direction of said thickness, and wherein theintersecting-direction stop-position selecting device comprises anintersecting-direction pressing device which selectively presses each ofthe two cam followers of the pair against a corresponding one of a pairof opposite side surfaces of the cam rib.
 4. An apparatus according toclaim 1, wherein the electronic component holder head comprises asucking pipe which sucks and holds, by vacuum, the electronic component.5. A system for mounting an electronic component on an object,comprising: an electronic component holder head positioning apparatuswhich positions at least one electronic component holder head forholding an electronic component, at a selected one of a plurality ofselectable positions of at least one stop station, the positioningapparatus comprising a holder head moving and stopping device whichmoves the electronic component holder head along a predeterminedmovement path and stops the holder head at said at least one stopstation on the movement path, and at least one of (a) at least oneon-path stop position selecting actuator which moves said at least oneelectronic component holder head to one of a plurality of first on-pathstop positions thereof which are spaced from each other on the movementpath, and thereby selects, as one of the selectable positions of thestop station, a corresponding one of a plurality of second on-path stoppositions which are spaced from each other on the movement path andwhich have a same position in a direction perpendicular to the movementpath, so that the holder head moving and stopping device stops, andthereby positions, the electronic component holder head at the selectedone second on-path stop position as the selected one selectable positionof the stop station, and (b) at least one intersecting-direction stopposition selecting actuator which moves said at least one electroniccomponent holder head to one of a plurality of firstintersecting-direction stop positions thereof which are spaced from eachother in a first direction intersecting the movement path, and therebyselects, as one of the selectable positions of the stop station, acorresponding one of a plurality of second intersecting-direction stoppositions which are spaced from each other in the first directionintersecting the movement path and which have a same position in asecond direction perpendicular to the first direction, so that theholder head moving and stopping device stops, and thereby positions, theelectronic component holder head at the selected one secondintersecting-direction stop position as the selected one selectableposition of the stop station; an electronic component supply devicewhich is provided at a first one of a plurality of stop stationscomprising said at least one stop station and which supplies anelectronic component to the electronic component holder head so thatsaid holder head holds the electronic component; and an objectsupporting and positioning device which is provided at a second one ofthe stop stations and which supports and positions an object on whichthe electronic component held by said holder head is to be mounted.